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package goja
import (
"bytes"
"errors"
"fmt"
"go/ast"
"hash/maphash"
"math"
"math/big"
"math/bits"
"math/rand"
"reflect"
"runtime"
"strconv"
"time"
"golang.org/x/text/collate"
js_ast "github.com/dop251/goja/ast"
"github.com/dop251/goja/file"
"github.com/dop251/goja/parser"
"github.com/dop251/goja/unistring"
)
const (
sqrt1_2 float64 = math . Sqrt2 / 2
deoptimiseRegexp = false
)
var (
typeCallable = reflect . TypeOf ( Callable ( nil ) )
typeValue = reflect . TypeOf ( ( * Value ) ( nil ) ) . Elem ( )
typeObject = reflect . TypeOf ( ( * Object ) ( nil ) )
typeTime = reflect . TypeOf ( time . Time { } )
typeBigInt = reflect . TypeOf ( ( * big . Int ) ( nil ) )
typeBytes = reflect . TypeOf ( ( [ ] byte ) ( nil ) )
)
type iterationKind int
const (
iterationKindKey iterationKind = iota
iterationKindValue
iterationKindKeyValue
)
type global struct {
stash stash
Object * Object
Array * Object
Function * Object
String * Object
Number * Object
BigInt * Object
Boolean * Object
RegExp * Object
Date * Object
Symbol * Object
Proxy * Object
Reflect * Object
Promise * Object
Math * Object
JSON * Object
AsyncFunction * Object
ArrayBuffer * Object
DataView * Object
TypedArray * Object
Uint8Array * Object
Uint8ClampedArray * Object
Int8Array * Object
Uint16Array * Object
Int16Array * Object
Uint32Array * Object
Int32Array * Object
Float32Array * Object
Float64Array * Object
BigInt64Array * Object
BigUint64Array * Object
WeakSet * Object
WeakMap * Object
Map * Object
Set * Object
Error * Object
AggregateError * Object
TypeError * Object
ReferenceError * Object
SyntaxError * Object
RangeError * Object
EvalError * Object
URIError * Object
GoError * Object
ObjectPrototype * Object
ArrayPrototype * Object
NumberPrototype * Object
BigIntPrototype * Object
StringPrototype * Object
BooleanPrototype * Object
FunctionPrototype * Object
RegExpPrototype * Object
DatePrototype * Object
SymbolPrototype * Object
ArrayBufferPrototype * Object
DataViewPrototype * Object
TypedArrayPrototype * Object
WeakSetPrototype * Object
WeakMapPrototype * Object
MapPrototype * Object
SetPrototype * Object
PromisePrototype * Object
GeneratorFunctionPrototype * Object
GeneratorFunction * Object
GeneratorPrototype * Object
AsyncFunctionPrototype * Object
IteratorPrototype * Object
ArrayIteratorPrototype * Object
MapIteratorPrototype * Object
SetIteratorPrototype * Object
StringIteratorPrototype * Object
RegExpStringIteratorPrototype * Object
ErrorPrototype * Object
Eval * Object
thrower * Object
stdRegexpProto * guardedObject
weakSetAdder * Object
weakMapAdder * Object
mapAdder * Object
setAdder * Object
arrayValues * Object
arrayToString * Object
stringproto_trimEnd * Object
stringproto_trimStart * Object
parseFloat , parseInt * Object
typedArrayValues * Object
}
type Flag int
const (
FLAG_NOT_SET Flag = iota
FLAG_FALSE
FLAG_TRUE
)
func ( f Flag ) Bool ( ) bool {
return f == FLAG_TRUE
}
func ToFlag ( b bool ) Flag {
if b {
return FLAG_TRUE
}
return FLAG_FALSE
}
type RandSource func ( ) float64
type Now func ( ) time . Time
type Runtime struct {
global global
globalObject * Object
stringSingleton * stringObject
rand RandSource
now Now
_collator * collate . Collator
parserOptions [ ] parser . Option
symbolRegistry map [ unistring . String ] * Symbol
fieldsInfoCache map [ reflect . Type ] * reflectFieldsInfo
methodsInfoCache map [ reflect . Type ] * reflectMethodsInfo
fieldNameMapper FieldNameMapper
vm * vm
hash * maphash . Hash
idSeq uint64
jobQueue [ ] func ( )
promiseRejectionTracker PromiseRejectionTracker
asyncContextTracker AsyncContextTracker
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GoData map [ string ] any
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}
type StackFrame struct {
prg * Program
funcName unistring . String
pc int
}
func ( f * StackFrame ) SrcName ( ) string {
if f . prg == nil {
return "<native>"
}
return f . prg . src . Name ( )
}
func ( f * StackFrame ) FuncName ( ) string {
if f . funcName == "" && f . prg == nil {
return "<native>"
}
if f . funcName == "" {
return "<anonymous>"
}
return f . funcName . String ( )
}
func ( f * StackFrame ) Position ( ) file . Position {
if f . prg == nil || f . prg . src == nil {
return file . Position { }
}
return f . prg . src . Position ( f . prg . sourceOffset ( f . pc ) )
}
func ( f * StackFrame ) WriteToValueBuilder ( b * StringBuilder ) {
if f . prg != nil {
if n := f . prg . funcName ; n != "" {
b . WriteString ( stringValueFromRaw ( n ) )
b . writeASCII ( " (" )
}
p := f . Position ( )
if p . Filename != "" {
b . WriteUTF8String ( p . Filename )
} else {
b . writeASCII ( "<eval>" )
}
b . WriteRune ( ':' )
b . writeASCII ( strconv . Itoa ( p . Line ) )
b . WriteRune ( ':' )
b . writeASCII ( strconv . Itoa ( p . Column ) )
b . WriteRune ( '(' )
b . writeASCII ( strconv . Itoa ( f . pc ) )
b . WriteRune ( ')' )
if f . prg . funcName != "" {
b . WriteRune ( ')' )
}
} else {
if f . funcName != "" {
b . WriteString ( stringValueFromRaw ( f . funcName ) )
b . writeASCII ( " (" )
}
b . writeASCII ( "native" )
if f . funcName != "" {
b . WriteRune ( ')' )
}
}
}
func ( f * StackFrame ) Write ( b * bytes . Buffer ) {
if f . prg != nil {
if n := f . prg . funcName ; n != "" {
b . WriteString ( n . String ( ) )
b . WriteString ( " (" )
}
p := f . Position ( )
if p . Filename != "" {
b . WriteString ( p . Filename )
} else {
b . WriteString ( "<eval>" )
}
b . WriteByte ( ':' )
b . WriteString ( strconv . Itoa ( p . Line ) )
b . WriteByte ( ':' )
b . WriteString ( strconv . Itoa ( p . Column ) )
b . WriteByte ( '(' )
b . WriteString ( strconv . Itoa ( f . pc ) )
b . WriteByte ( ')' )
if f . prg . funcName != "" {
b . WriteByte ( ')' )
}
} else {
if f . funcName != "" {
b . WriteString ( f . funcName . String ( ) )
b . WriteString ( " (" )
}
b . WriteString ( "native" )
if f . funcName != "" {
b . WriteByte ( ')' )
}
}
}
// An un-catchable exception is not catchable by try/catch statements (finally is not executed either),
// but it is returned as an error to a Go caller rather than causing a panic.
type uncatchableException interface {
error
_uncatchableException ( )
}
type Exception struct {
val Value
stack [ ] StackFrame
}
type baseUncatchableException struct {
Exception
}
func ( e * baseUncatchableException ) _uncatchableException ( ) { }
type InterruptedError struct {
baseUncatchableException
iface interface { }
}
func ( e * InterruptedError ) Unwrap ( ) error {
if err , ok := e . iface . ( error ) ; ok {
return err
}
return nil
}
type StackOverflowError struct {
baseUncatchableException
}
func ( e * InterruptedError ) Value ( ) interface { } {
return e . iface
}
func ( e * InterruptedError ) String ( ) string {
if e == nil {
return "<nil>"
}
var b bytes . Buffer
if e . iface != nil {
b . WriteString ( fmt . Sprint ( e . iface ) )
b . WriteByte ( '\n' )
}
e . writeFullStack ( & b )
return b . String ( )
}
func ( e * InterruptedError ) Error ( ) string {
if e == nil || e . iface == nil {
return "<nil>"
}
var b bytes . Buffer
b . WriteString ( fmt . Sprint ( e . iface ) )
e . writeShortStack ( & b )
return b . String ( )
}
func ( e * Exception ) writeFullStack ( b * bytes . Buffer ) {
for _ , frame := range e . stack {
b . WriteString ( "\tat " )
frame . Write ( b )
b . WriteByte ( '\n' )
}
}
func ( e * Exception ) writeShortStack ( b * bytes . Buffer ) {
if len ( e . stack ) > 0 && ( e . stack [ 0 ] . prg != nil || e . stack [ 0 ] . funcName != "" ) {
b . WriteString ( " at " )
e . stack [ 0 ] . Write ( b )
}
}
func ( e * Exception ) String ( ) string {
if e == nil {
return "<nil>"
}
var b bytes . Buffer
if e . val != nil {
b . WriteString ( e . val . String ( ) )
b . WriteByte ( '\n' )
}
e . writeFullStack ( & b )
return b . String ( )
}
func ( e * Exception ) Error ( ) string {
if e == nil {
return "<nil>"
}
var b bytes . Buffer
if e . val != nil {
b . WriteString ( e . val . String ( ) )
}
e . writeShortStack ( & b )
return b . String ( )
}
func ( e * Exception ) Value ( ) Value {
return e . val
}
func ( e * Exception ) Unwrap ( ) error {
if obj , ok := e . val . ( * Object ) ; ok {
if obj . runtime . getGoError ( ) . self . hasInstance ( obj ) {
if val := obj . Get ( "value" ) ; val != nil {
e1 , _ := val . Export ( ) . ( error )
return e1
}
}
}
return nil
}
func ( e * Exception ) Stack ( ) [ ] StackFrame {
return e . stack
}
func ( r * Runtime ) createIterProto ( val * Object ) objectImpl {
o := newBaseObjectObj ( val , r . global . ObjectPrototype , classObject )
o . _putSym ( SymIterator , valueProp ( r . newNativeFunc ( r . returnThis , "[Symbol.iterator]" , 0 ) , true , false , true ) )
return o
}
func ( r * Runtime ) getIteratorPrototype ( ) * Object {
var o * Object
if o = r . global . IteratorPrototype ; o == nil {
o = & Object { runtime : r }
r . global . IteratorPrototype = o
o . self = r . createIterProto ( o )
}
return o
}
func ( r * Runtime ) init ( ) {
r . rand = rand . Float64
r . now = time . Now
r . global . ObjectPrototype = & Object { runtime : r }
r . newTemplatedObject ( getObjectProtoTemplate ( ) , r . global . ObjectPrototype )
r . globalObject = & Object { runtime : r }
r . newTemplatedObject ( getGlobalObjectTemplate ( ) , r . globalObject )
r . vm = & vm {
r : r ,
}
r . vm . init ( )
}
func ( r * Runtime ) typeErrorResult ( throw bool , args ... interface { } ) {
if throw {
panic ( r . NewTypeError ( args ... ) )
}
}
func ( r * Runtime ) newError ( typ * Object , format string , args ... interface { } ) Value {
var msg string
if len ( args ) > 0 {
msg = fmt . Sprintf ( format , args ... )
} else {
msg = format
}
return r . builtin_new ( typ , [ ] Value { newStringValue ( msg ) } )
}
func ( r * Runtime ) throwReferenceError ( name unistring . String ) {
panic ( r . newReferenceError ( name ) )
}
func ( r * Runtime ) newReferenceError ( name unistring . String ) Value {
return r . newError ( r . getReferenceError ( ) , "%s is not defined" , name )
}
func ( r * Runtime ) newSyntaxError ( msg string , offset int ) Value {
return r . builtin_new ( r . getSyntaxError ( ) , [ ] Value { newStringValue ( msg ) } )
}
func newBaseObjectObj ( obj , proto * Object , class string ) * baseObject {
o := & baseObject {
class : class ,
val : obj ,
extensible : true ,
prototype : proto ,
}
obj . self = o
o . init ( )
return o
}
func newGuardedObj ( proto * Object , class string ) * guardedObject {
return & guardedObject {
baseObject : baseObject {
class : class ,
extensible : true ,
prototype : proto ,
} ,
}
}
func ( r * Runtime ) newBaseObject ( proto * Object , class string ) ( o * baseObject ) {
v := & Object { runtime : r }
return newBaseObjectObj ( v , proto , class )
}
func ( r * Runtime ) newGuardedObject ( proto * Object , class string ) ( o * guardedObject ) {
v := & Object { runtime : r }
o = newGuardedObj ( proto , class )
v . self = o
o . val = v
o . init ( )
return
}
func ( r * Runtime ) NewObject ( ) ( v * Object ) {
return r . newBaseObject ( r . global . ObjectPrototype , classObject ) . val
}
// CreateObject creates an object with given prototype. Equivalent of Object.create(proto).
func ( r * Runtime ) CreateObject ( proto * Object ) * Object {
return r . newBaseObject ( proto , classObject ) . val
}
func ( r * Runtime ) NewArray ( items ... interface { } ) * Object {
values := make ( [ ] Value , len ( items ) )
for i , item := range items {
values [ i ] = r . ToValue ( item )
}
return r . newArrayValues ( values )
}
func ( r * Runtime ) NewTypeError ( args ... interface { } ) * Object {
msg := ""
if len ( args ) > 0 {
f , _ := args [ 0 ] . ( string )
msg = fmt . Sprintf ( f , args [ 1 : ] ... )
}
return r . builtin_new ( r . getTypeError ( ) , [ ] Value { newStringValue ( msg ) } )
}
func ( r * Runtime ) NewGoError ( err error ) * Object {
e := r . newError ( r . getGoError ( ) , err . Error ( ) ) . ( * Object )
e . Set ( "value" , err )
return e
}
func ( r * Runtime ) newFunc ( name unistring . String , length int , strict bool ) ( f * funcObject ) {
f = & funcObject { }
r . initBaseJsFunction ( & f . baseJsFuncObject , strict )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
return
}
func ( r * Runtime ) newAsyncFunc ( name unistring . String , length int , strict bool ) ( f * asyncFuncObject ) {
f = & asyncFuncObject { }
r . initBaseJsFunction ( & f . baseJsFuncObject , strict )
f . class = classFunction
f . prototype = r . getAsyncFunctionPrototype ( )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
return
}
func ( r * Runtime ) newGeneratorFunc ( name unistring . String , length int , strict bool ) ( f * generatorFuncObject ) {
f = & generatorFuncObject { }
r . initBaseJsFunction ( & f . baseJsFuncObject , strict )
f . class = classFunction
f . prototype = r . getGeneratorFunctionPrototype ( )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
f . _putProp ( "prototype" , r . newBaseObject ( r . getGeneratorPrototype ( ) , classObject ) . val , true , false , false )
return
}
func ( r * Runtime ) newClassFunc ( name unistring . String , length int , proto * Object , derived bool ) ( f * classFuncObject ) {
v := & Object { runtime : r }
f = & classFuncObject { }
f . class = classFunction
f . val = v
f . extensible = true
f . strict = true
f . derived = derived
v . self = f
f . prototype = proto
f . init ( name , intToValue ( int64 ( length ) ) )
return
}
func ( r * Runtime ) initBaseJsFunction ( f * baseJsFuncObject , strict bool ) {
v := & Object { runtime : r }
f . class = classFunction
f . val = v
f . extensible = true
f . strict = strict
f . prototype = r . getFunctionPrototype ( )
}
func ( r * Runtime ) newMethod ( name unistring . String , length int , strict bool ) ( f * methodFuncObject ) {
f = & methodFuncObject { }
r . initBaseJsFunction ( & f . baseJsFuncObject , strict )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
return
}
func ( r * Runtime ) newGeneratorMethod ( name unistring . String , length int , strict bool ) ( f * generatorMethodFuncObject ) {
f = & generatorMethodFuncObject { }
r . initBaseJsFunction ( & f . baseJsFuncObject , strict )
f . prototype = r . getGeneratorFunctionPrototype ( )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
f . _putProp ( "prototype" , r . newBaseObject ( r . getGeneratorPrototype ( ) , classObject ) . val , true , false , false )
return
}
func ( r * Runtime ) newAsyncMethod ( name unistring . String , length int , strict bool ) ( f * asyncMethodFuncObject ) {
f = & asyncMethodFuncObject { }
r . initBaseJsFunction ( & f . baseJsFuncObject , strict )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
return
}
func ( r * Runtime ) initArrowFunc ( f * arrowFuncObject , strict bool ) {
r . initBaseJsFunction ( & f . baseJsFuncObject , strict )
f . newTarget = r . vm . newTarget
}
func ( r * Runtime ) newArrowFunc ( name unistring . String , length int , strict bool ) ( f * arrowFuncObject ) {
f = & arrowFuncObject { }
r . initArrowFunc ( f , strict )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
return
}
func ( r * Runtime ) newAsyncArrowFunc ( name unistring . String , length int , strict bool ) ( f * asyncArrowFuncObject ) {
f = & asyncArrowFuncObject { }
r . initArrowFunc ( & f . arrowFuncObject , strict )
f . class = classObject
f . prototype = r . getAsyncFunctionPrototype ( )
f . val . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
return
}
func ( r * Runtime ) newNativeConstructor ( call func ( ConstructorCall ) * Object , name unistring . String , length int64 ) * Object {
v := & Object { runtime : r }
f := & nativeFuncObject {
baseFuncObject : baseFuncObject {
baseObject : baseObject {
class : classFunction ,
val : v ,
extensible : true ,
prototype : r . getFunctionPrototype ( ) ,
} ,
} ,
}
f . f = func ( c FunctionCall ) Value {
thisObj , _ := c . This . ( * Object )
if thisObj != nil {
res := call ( ConstructorCall {
This : thisObj ,
Arguments : c . Arguments ,
} )
if res == nil {
return _undefined
}
return res
}
return f . defaultConstruct ( call , c . Arguments , nil )
}
f . construct = func ( args [ ] Value , newTarget * Object ) * Object {
return f . defaultConstruct ( call , args , newTarget )
}
v . self = f
f . init ( name , intToValue ( length ) )
proto := r . NewObject ( )
proto . self . _putProp ( "constructor" , v , true , false , true )
f . _putProp ( "prototype" , proto , true , false , false )
return v
}
func ( r * Runtime ) newNativeConstructOnly ( v * Object , ctor func ( args [ ] Value , newTarget * Object ) * Object , defaultProto * Object , name unistring . String , length int64 ) * nativeFuncObject {
return r . newNativeFuncAndConstruct ( v , func ( call FunctionCall ) Value {
return ctor ( call . Arguments , nil )
} ,
func ( args [ ] Value , newTarget * Object ) * Object {
if newTarget == nil {
newTarget = v
}
return ctor ( args , newTarget )
} , defaultProto , name , intToValue ( length ) )
}
func ( r * Runtime ) newNativeFuncAndConstruct ( v * Object , call func ( call FunctionCall ) Value , ctor func ( args [ ] Value , newTarget * Object ) * Object , defaultProto * Object , name unistring . String , l Value ) * nativeFuncObject {
if v == nil {
v = & Object { runtime : r }
}
f := & nativeFuncObject {
baseFuncObject : baseFuncObject {
baseObject : baseObject {
class : classFunction ,
val : v ,
extensible : true ,
prototype : r . getFunctionPrototype ( ) ,
} ,
} ,
f : call ,
construct : ctor ,
}
v . self = f
f . init ( name , l )
if defaultProto != nil {
f . _putProp ( "prototype" , defaultProto , false , false , false )
}
return f
}
func ( r * Runtime ) newNativeFunc ( call func ( FunctionCall ) Value , name unistring . String , length int ) * Object {
v := & Object { runtime : r }
f := & nativeFuncObject {
baseFuncObject : baseFuncObject {
baseObject : baseObject {
class : classFunction ,
val : v ,
extensible : true ,
prototype : r . getFunctionPrototype ( ) ,
} ,
} ,
f : call ,
}
v . self = f
f . init ( name , intToValue ( int64 ( length ) ) )
return v
}
func ( r * Runtime ) newWrappedFunc ( value reflect . Value ) * Object {
v := & Object { runtime : r }
f := & wrappedFuncObject {
nativeFuncObject : nativeFuncObject {
baseFuncObject : baseFuncObject {
baseObject : baseObject {
class : classFunction ,
val : v ,
extensible : true ,
prototype : r . getFunctionPrototype ( ) ,
} ,
} ,
f : r . wrapReflectFunc ( value ) ,
} ,
wrapped : value ,
}
v . self = f
name := unistring . NewFromString ( runtime . FuncForPC ( value . Pointer ( ) ) . Name ( ) )
f . init ( name , intToValue ( int64 ( value . Type ( ) . NumIn ( ) ) ) )
return v
}
func ( r * Runtime ) newNativeFuncConstructObj ( v * Object , construct func ( args [ ] Value , proto * Object ) * Object , name unistring . String , proto * Object , length int ) * nativeFuncObject {
f := & nativeFuncObject {
baseFuncObject : baseFuncObject {
baseObject : baseObject {
class : classFunction ,
val : v ,
extensible : true ,
prototype : r . getFunctionPrototype ( ) ,
} ,
} ,
f : r . constructToCall ( construct , proto ) ,
construct : r . wrapNativeConstruct ( construct , v , proto ) ,
}
f . init ( name , intToValue ( int64 ( length ) ) )
if proto != nil {
f . _putProp ( "prototype" , proto , false , false , false )
}
return f
}
func ( r * Runtime ) newNativeFuncConstruct ( v * Object , construct func ( args [ ] Value , proto * Object ) * Object , name unistring . String , prototype * Object , length int64 ) * Object {
return r . newNativeFuncConstructProto ( v , construct , name , prototype , r . getFunctionPrototype ( ) , length )
}
func ( r * Runtime ) newNativeFuncConstructProto ( v * Object , construct func ( args [ ] Value , proto * Object ) * Object , name unistring . String , prototype , proto * Object , length int64 ) * Object {
f := & nativeFuncObject { }
f . class = classFunction
f . val = v
f . extensible = true
v . self = f
f . prototype = proto
f . f = r . constructToCall ( construct , prototype )
f . construct = r . wrapNativeConstruct ( construct , v , prototype )
f . init ( name , intToValue ( length ) )
if prototype != nil {
f . _putProp ( "prototype" , prototype , false , false , false )
}
return v
}
func ( r * Runtime ) newPrimitiveObject ( value Value , proto * Object , class string ) * Object {
v := & Object { runtime : r }
o := & primitiveValueObject { }
o . class = class
o . val = v
o . extensible = true
v . self = o
o . prototype = proto
o . pValue = value
o . init ( )
return v
}
func ( r * Runtime ) builtin_Number ( call FunctionCall ) Value {
if len ( call . Arguments ) > 0 {
switch t := call . Arguments [ 0 ] . ( type ) {
case * Object :
primValue := t . toPrimitiveNumber ( )
if bigint , ok := primValue . ( * valueBigInt ) ; ok {
return intToValue ( ( * big . Int ) ( bigint ) . Int64 ( ) )
}
return primValue . ToNumber ( )
case * valueBigInt :
return intToValue ( ( * big . Int ) ( t ) . Int64 ( ) )
default :
return t . ToNumber ( )
}
} else {
return valueInt ( 0 )
}
}
func ( r * Runtime ) builtin_newNumber ( args [ ] Value , proto * Object ) * Object {
var v Value
if len ( args ) > 0 {
switch t := args [ 0 ] . ( type ) {
case * Object :
primValue := t . toPrimitiveNumber ( )
if bigint , ok := primValue . ( * valueBigInt ) ; ok {
v = intToValue ( ( * big . Int ) ( bigint ) . Int64 ( ) )
} else {
v = primValue . ToNumber ( )
}
case * valueBigInt :
v = intToValue ( ( * big . Int ) ( t ) . Int64 ( ) )
default :
v = t . ToNumber ( )
}
} else {
v = intToValue ( 0 )
}
return r . newPrimitiveObject ( v , proto , classNumber )
}
func ( r * Runtime ) builtin_Boolean ( call FunctionCall ) Value {
if len ( call . Arguments ) > 0 {
if call . Arguments [ 0 ] . ToBoolean ( ) {
return valueTrue
} else {
return valueFalse
}
} else {
return valueFalse
}
}
func ( r * Runtime ) builtin_newBoolean ( args [ ] Value , proto * Object ) * Object {
var v Value
if len ( args ) > 0 {
if args [ 0 ] . ToBoolean ( ) {
v = valueTrue
} else {
v = valueFalse
}
} else {
v = valueFalse
}
return r . newPrimitiveObject ( v , proto , classBoolean )
}
func ( r * Runtime ) builtin_new ( construct * Object , args [ ] Value ) * Object {
return r . toConstructor ( construct ) ( args , construct )
}
func ( r * Runtime ) builtin_thrower ( call FunctionCall ) Value {
obj := r . toObject ( call . This )
strict := true
switch fn := obj . self . ( type ) {
case * funcObject :
strict = fn . strict
}
r . typeErrorResult ( strict , "'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them" )
return nil
}
func ( r * Runtime ) eval ( srcVal String , direct , strict bool ) Value {
src := escapeInvalidUtf16 ( srcVal )
vm := r . vm
inGlobal := true
if direct {
for s := vm . stash ; s != nil ; s = s . outer {
if s . isVariable ( ) {
inGlobal = false
break
}
}
}
vm . pushCtx ( )
funcObj := _undefined
if ! direct {
vm . stash = & r . global . stash
vm . privEnv = nil
} else {
if sb := vm . sb ; sb > 0 {
funcObj = vm . stack [ sb - 1 ]
}
}
p , err := r . compile ( "<eval>" , src , strict , inGlobal , r . vm )
if err != nil {
panic ( err )
}
vm . prg = p
vm . pc = 0
vm . args = 0
vm . result = _undefined
vm . push ( funcObj )
vm . sb = vm . sp
vm . push ( nil ) // this
ex := vm . runTry ( )
retval := vm . result
vm . popCtx ( )
if ex != nil {
panic ( ex )
}
vm . sp -= 2
return retval
}
func ( r * Runtime ) builtin_eval ( call FunctionCall ) Value {
if len ( call . Arguments ) == 0 {
return _undefined
}
if str , ok := call . Arguments [ 0 ] . ( String ) ; ok {
return r . eval ( str , false , false )
}
return call . Arguments [ 0 ]
}
func ( r * Runtime ) constructToCall ( construct func ( args [ ] Value , proto * Object ) * Object , proto * Object ) func ( call FunctionCall ) Value {
return func ( call FunctionCall ) Value {
return construct ( call . Arguments , proto )
}
}
func ( r * Runtime ) wrapNativeConstruct ( c func ( args [ ] Value , proto * Object ) * Object , ctorObj , defProto * Object ) func ( args [ ] Value , newTarget * Object ) * Object {
if c == nil {
return nil
}
return func ( args [ ] Value , newTarget * Object ) * Object {
var proto * Object
if newTarget != nil {
proto = r . getPrototypeFromCtor ( newTarget , ctorObj , defProto )
} else {
proto = defProto
}
return c ( args , proto )
}
}
func ( r * Runtime ) toCallable ( v Value ) func ( FunctionCall ) Value {
if call , ok := r . toObject ( v ) . self . assertCallable ( ) ; ok {
return call
}
r . typeErrorResult ( true , "Value is not callable: %s" , v . toString ( ) )
return nil
}
func ( r * Runtime ) checkObjectCoercible ( v Value ) {
switch v . ( type ) {
case valueUndefined , valueNull :
r . typeErrorResult ( true , "Value is not object coercible" )
}
}
func toInt8 ( v Value ) int8 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return int8 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return int8 ( int64 ( f ) )
}
}
return 0
}
func toUint8 ( v Value ) uint8 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return uint8 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return uint8 ( int64 ( f ) )
}
}
return 0
}
func toUint8Clamp ( v Value ) uint8 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
if i < 0 {
return 0
}
if i <= 255 {
return uint8 ( i )
}
return 255
}
if num , ok := v . ( valueFloat ) ; ok {
num := float64 ( num )
if ! math . IsNaN ( num ) {
if num < 0 {
return 0
}
if num > 255 {
return 255
}
f := math . Floor ( num )
f1 := f + 0.5
if f1 < num {
return uint8 ( f + 1 )
}
if f1 > num {
return uint8 ( f )
}
r := uint8 ( f )
if r & 1 != 0 {
return r + 1
}
return r
}
}
return 0
}
func toInt16 ( v Value ) int16 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return int16 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return int16 ( int64 ( f ) )
}
}
return 0
}
func toUint16 ( v Value ) uint16 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return uint16 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return uint16 ( int64 ( f ) )
}
}
return 0
}
func toInt32 ( v Value ) int32 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return int32 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return int32 ( int64 ( f ) )
}
}
return 0
}
func toUint32 ( v Value ) uint32 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return uint32 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return uint32 ( int64 ( f ) )
}
}
return 0
}
func toInt64 ( v Value ) int64 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return int64 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return int64 ( f )
}
}
return 0
}
func toUint64 ( v Value ) uint64 {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return uint64 ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return uint64 ( int64 ( f ) )
}
}
return 0
}
func toInt ( v Value ) int {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return int ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return int ( f )
}
}
return 0
}
func toUint ( v Value ) uint {
v = v . ToNumber ( )
if i , ok := v . ( valueInt ) ; ok {
return uint ( i )
}
if f , ok := v . ( valueFloat ) ; ok {
f := float64 ( f )
if ! math . IsNaN ( f ) && ! math . IsInf ( f , 0 ) {
return uint ( int64 ( f ) )
}
}
return 0
}
func toFloat32 ( v Value ) float32 {
return float32 ( v . ToFloat ( ) )
}
func toLength ( v Value ) int64 {
if v == nil {
return 0
}
i := v . ToInteger ( )
if i < 0 {
return 0
}
if i >= maxInt {
return maxInt - 1
}
return i
}
func ( r * Runtime ) toLengthUint32 ( v Value ) uint32 {
var intVal int64
repeat :
switch num := v . ( type ) {
case valueInt :
intVal = int64 ( num )
case valueFloat :
if v != _negativeZero {
if i , ok := floatToInt ( float64 ( num ) ) ; ok {
intVal = i
} else {
goto fail
}
}
case String :
v = num . ToNumber ( )
goto repeat
default :
// Legacy behaviour as specified in https://tc39.es/ecma262/#sec-arraysetlength (see the note)
n2 := toUint32 ( v )
n1 := v . ToNumber ( )
if f , ok := n1 . ( valueFloat ) ; ok {
f := float64 ( f )
if f != 0 || ! math . Signbit ( f ) {
goto fail
}
}
if n1 . ToInteger ( ) != int64 ( n2 ) {
goto fail
}
return n2
}
if intVal >= 0 && intVal <= math . MaxUint32 {
return uint32 ( intVal )
}
fail :
panic ( r . newError ( r . getRangeError ( ) , "Invalid array length" ) )
}
func toIntStrict ( i int64 ) int {
if bits . UintSize == 32 {
if i > math . MaxInt32 || i < math . MinInt32 {
panic ( rangeError ( "Integer value overflows 32-bit int" ) )
}
}
return int ( i )
}
func toIntClamp ( i int64 ) int {
if bits . UintSize == 32 {
if i > math . MaxInt32 {
return math . MaxInt32
}
if i < math . MinInt32 {
return math . MinInt32
}
}
return int ( i )
}
func ( r * Runtime ) toIndex ( v Value ) int {
num := v . ToInteger ( )
if num >= 0 && num < maxInt {
if bits . UintSize == 32 && num >= math . MaxInt32 {
panic ( r . newError ( r . getRangeError ( ) , "Index %s overflows int" , v . String ( ) ) )
}
return int ( num )
}
panic ( r . newError ( r . getRangeError ( ) , "Invalid index %s" , v . String ( ) ) )
}
func ( r * Runtime ) toBoolean ( b bool ) Value {
if b {
return valueTrue
} else {
return valueFalse
}
}
// New creates an instance of a Javascript runtime that can be used to run code. Multiple instances may be created and
// used simultaneously, however it is not possible to pass JS values across runtimes.
func New ( ) * Runtime {
r := & Runtime { }
r . init ( )
return r
}
// Compile creates an internal representation of the JavaScript code that can be later run using the Runtime.RunProgram()
// method. This representation is not linked to a runtime in any way and can be run in multiple runtimes (possibly
// at the same time).
func Compile ( name , src string , strict bool ) ( * Program , error ) {
return compile ( name , src , strict , true , nil )
}
// CompileAST creates an internal representation of the JavaScript code that can be later run using the Runtime.RunProgram()
// method. This representation is not linked to a runtime in any way and can be run in multiple runtimes (possibly
// at the same time).
func CompileAST ( prg * js_ast . Program , strict bool ) ( * Program , error ) {
return compileAST ( prg , strict , true , nil )
}
// MustCompile is like Compile but panics if the code cannot be compiled.
// It simplifies safe initialization of global variables holding compiled JavaScript code.
func MustCompile ( name , src string , strict bool ) * Program {
prg , err := Compile ( name , src , strict )
if err != nil {
panic ( err )
}
return prg
}
// Parse takes a source string and produces a parsed AST. Use this function if you want to pass options
// to the parser, e.g.:
//
// p, err := Parse("test.js", "var a = true", parser.WithDisableSourceMaps)
// if err != nil { /* ... */ }
// prg, err := CompileAST(p, true)
// // ...
//
// Otherwise use Compile which combines both steps.
func Parse ( name , src string , options ... parser . Option ) ( prg * js_ast . Program , err error ) {
prg , err1 := parser . ParseFile ( nil , name , src , 0 , options ... )
if err1 != nil {
// FIXME offset
err = & CompilerSyntaxError {
CompilerError : CompilerError {
Message : err1 . Error ( ) ,
} ,
}
}
return
}
func compile ( name , src string , strict , inGlobal bool , evalVm * vm , parserOptions ... parser . Option ) ( p * Program , err error ) {
prg , err := Parse ( name , src , parserOptions ... )
if err != nil {
return
}
return compileAST ( prg , strict , inGlobal , evalVm )
}
func compileAST ( prg * js_ast . Program , strict , inGlobal bool , evalVm * vm ) ( p * Program , err error ) {
c := newCompiler ( )
defer func ( ) {
if x := recover ( ) ; x != nil {
p = nil
switch x1 := x . ( type ) {
case * CompilerSyntaxError :
err = x1
default :
panic ( x )
}
}
} ( )
c . compile ( prg , strict , inGlobal , evalVm )
p = c . p
return
}
func ( r * Runtime ) compile ( name , src string , strict , inGlobal bool , evalVm * vm ) ( p * Program , err error ) {
p , err = compile ( name , src , strict , inGlobal , evalVm , r . parserOptions ... )
if err != nil {
switch x1 := err . ( type ) {
case * CompilerSyntaxError :
err = & Exception {
val : r . builtin_new ( r . getSyntaxError ( ) , [ ] Value { newStringValue ( x1 . Error ( ) ) } ) ,
}
case * CompilerReferenceError :
err = & Exception {
val : r . newError ( r . getReferenceError ( ) , x1 . Message ) ,
} // TODO proper message
}
}
return
}
// RunString executes the given string in the global context.
func ( r * Runtime ) RunString ( str string ) ( Value , error ) {
return r . RunScript ( "" , str )
}
// RunScript executes the given string in the global context.
func ( r * Runtime ) RunScript ( name , src string ) ( Value , error ) {
p , err := r . compile ( name , src , false , true , nil )
if err != nil {
return nil , err
}
return r . RunProgram ( p )
}
func isUncatchableException ( e error ) bool {
for ; e != nil ; e = errors . Unwrap ( e ) {
if _ , ok := e . ( uncatchableException ) ; ok {
return true
}
}
return false
}
func asUncatchableException ( v interface { } ) error {
switch v := v . ( type ) {
case uncatchableException :
return v
case error :
if isUncatchableException ( v ) {
return v
}
}
return nil
}
// RunProgram executes a pre-compiled (see Compile()) code in the global context.
func ( r * Runtime ) RunProgram ( p * Program ) ( result Value , err error ) {
vm := r . vm
recursive := len ( vm . callStack ) > 0
defer func ( ) {
if recursive {
vm . sp -= 2
vm . popCtx ( )
} else {
vm . callStack = vm . callStack [ : len ( vm . callStack ) - 1 ]
}
if x := recover ( ) ; x != nil {
if ex := asUncatchableException ( x ) ; ex != nil {
err = ex
if len ( vm . callStack ) == 0 {
r . leaveAbrupt ( )
}
} else {
panic ( x )
}
}
} ( )
if recursive {
vm . pushCtx ( )
vm . stash = & r . global . stash
vm . privEnv = nil
vm . newTarget = nil
vm . args = 0
sp := vm . sp
vm . stack . expand ( sp + 1 )
vm . stack [ sp ] = _undefined // 'callee'
vm . stack [ sp + 1 ] = nil // 'this'
vm . sb = sp + 1
vm . sp = sp + 2
} else {
vm . callStack = append ( vm . callStack , context { } )
}
vm . prg = p
vm . pc = 0
vm . result = _undefined
ex := vm . runTry ( )
if ex == nil {
result = r . vm . result
} else {
err = ex
}
if recursive {
vm . clearStack ( )
} else {
vm . prg = nil
vm . sb = - 1
r . leave ( )
}
return
}
// CaptureCallStack appends the current call stack frames to the stack slice (which may be nil) up to the specified depth.
// The most recent frame will be the first one.
// If depth <= 0 or more than the number of available frames, returns the entire stack.
// This method is not safe for concurrent use and should only be called by a Go function that is
// called from a running script.
func ( r * Runtime ) CaptureCallStack ( depth int , stack [ ] StackFrame ) [ ] StackFrame {
l := len ( r . vm . callStack )
var offset int
if depth > 0 {
offset = l - depth + 1
if offset < 0 {
offset = 0
}
}
if stack == nil {
stack = make ( [ ] StackFrame , 0 , l - offset + 1 )
}
return r . vm . captureStack ( stack , offset )
}
// Interrupt a running JavaScript. The corresponding Go call will return an *InterruptedError containing v.
// If the interrupt propagates until the stack is empty the currently queued promise resolve/reject jobs will be cleared
// without being executed. This is the same time they would be executed otherwise.
// Note, it only works while in JavaScript code, it does not interrupt native Go functions (which includes all built-ins).
// If the runtime is currently not running, it will be immediately interrupted on the next Run*() call.
// To avoid that use ClearInterrupt()
func ( r * Runtime ) Interrupt ( v interface { } ) {
r . vm . Interrupt ( v )
}
// ClearInterrupt resets the interrupt flag. Typically this needs to be called before the runtime
// is made available for re-use if there is a chance it could have been interrupted with Interrupt().
// Otherwise if Interrupt() was called when runtime was not running (e.g. if it had already finished)
// so that Interrupt() didn't actually trigger, an attempt to use the runtime will immediately cause
// an interruption. It is up to the user to ensure proper synchronisation so that ClearInterrupt() is
// only called when the runtime has finished and there is no chance of a concurrent Interrupt() call.
func ( r * Runtime ) ClearInterrupt ( ) {
r . vm . ClearInterrupt ( )
}
/ *
ToValue converts a Go value into a JavaScript value of a most appropriate type . Structural types ( such as structs , maps
and slices ) are wrapped so that changes are reflected on the original value which can be retrieved using Value . Export ( ) .
WARNING ! These wrapped Go values do not behave in the same way as native ECMAScript values . If you plan to modify
them in ECMAScript , bear in mind the following caveats :
1. If a regular JavaScript Object is assigned as an element of a wrapped Go struct , map or array , it is
Export ( ) ' ed and therefore copied . This may result in an unexpected behaviour in JavaScript :
m := map [ string ] interface { } { }
vm . Set ( "m" , m )
vm . RunString ( `
var obj = { test : false } ;
m . obj = obj ; // obj gets Export()'ed, i.e. copied to a new map[string]interface{} and then this map is set as m["obj"]
obj . test = true ; // note, m.obj.test is still false
` )
fmt . Println ( m [ "obj" ] . ( map [ string ] interface { } ) [ "test" ] ) // prints "false"
2. Be careful with nested non - pointer compound types ( structs , slices and arrays ) if you modify them in
ECMAScript . Better avoid it at all if possible . One of the fundamental differences between ECMAScript and Go is in
the former all Objects are references whereas in Go you can have a literal struct or array . Consider the following
example :
type S struct {
Field int
}
a := [ ] S { { 1 } , { 2 } } // slice of literal structs
vm . Set ( "a" , & a )
vm . RunString ( `
let tmp = { Field : 1 } ;
a [ 0 ] = tmp ;
a [ 1 ] = tmp ;
tmp . Field = 2 ;
` )
In ECMAScript one would expect a [ 0 ] . Field and a [ 1 ] . Field to be equal to 2 , but this is really not possible
( or at least non - trivial without some complex reference tracking ) .
To cover the most common use cases and to avoid excessive memory allocation , the following ' copy - on - change ' mechanism
is implemented ( for both arrays and structs ) :
* When a nested compound value is accessed , the returned ES value becomes a reference to the literal value .
This ensures that things like ' a [ 0 ] . Field = 1 ' work as expected and simple access to ' a [ 0 ] . Field ' does not result
in copying of a [ 0 ] .
* The original container ( 'a' in our case ) keeps track of the returned reference value and if a [ 0 ] is reassigned
( e . g . by direct assignment , deletion or shrinking the array ) the old a [ 0 ] is copied and the earlier returned value
becomes a reference to the copy :
let tmp = a [ 0 ] ; // no copy, tmp is a reference to a[0]
tmp . Field = 1 ; // a[0].Field === 1 after this
a [ 0 ] = { Field : 2 } ; // tmp is now a reference to a copy of the old value (with Field === 1)
a [ 0 ] . Field == = 2 && tmp . Field == = 1 ; // true
* Array value swaps caused by in - place sort ( using Array . prototype . sort ( ) ) do not count as re - assignments , instead
the references are adjusted to point to the new indices .
* Assignment to an inner compound value always does a copy ( and sometimes type conversion ) :
a [ 1 ] = tmp ; // a[1] is now a copy of tmp
tmp . Field = 3 ; // does not affect a[1].Field
3. Non - addressable structs , slices and arrays get copied . This sometimes may lead to a confusion as assigning to
inner fields does not appear to work :
a1 := [ ] interface { } { S { 1 } , S { 2 } }
vm . Set ( "a1" , & a1 )
vm . RunString ( `
a1 [ 0 ] . Field == = 1 ; // true
a1 [ 0 ] . Field = 2 ;
a1 [ 0 ] . Field == = 2 ; // FALSE, because what it really did was copy a1[0] set its Field to 2 and immediately drop it
` )
An alternative would be making a1 [ 0 ] . Field a non - writable property which would probably be more in line with
ECMAScript , however it would require to manually copy the value if it does need to be modified which may be
impractical .
Note , the same applies to slices . If a slice is passed by value ( not as a pointer ) , resizing the slice does not reflect on the original
value . Moreover , extending the slice may result in the underlying array being re - allocated and copied .
For example :
a := [ ] interface { } { 1 }
vm . Set ( "a" , a )
vm . RunString ( ` a.push(2); a[0] = 0; ` )
fmt . Println ( a [ 0 ] ) // prints "1"
Notes on individual types :
# Primitive types
Primitive types ( numbers , string , bool ) are converted to the corresponding JavaScript primitives . These values
are goroutine - safe and can be transferred between runtimes .
# Strings
Because of the difference in internal string representation between ECMAScript ( which uses UTF - 16 ) and Go ( which uses
UTF - 8 ) conversion from JS to Go may be lossy . In particular , code points that can be part of UTF - 16 surrogate pairs
( 0xD800 - 0xDFFF ) cannot be represented in UTF - 8 unless they form a valid surrogate pair and are replaced with
utf8 . RuneError .
The string value must be a valid UTF - 8. If it is not , invalid characters are replaced with utf8 . RuneError , but
the behaviour of a subsequent Export ( ) is unspecified ( it may return the original value , or a value with replaced
invalid characters ) .
# Nil
Nil is converted to null .
# Functions
func ( FunctionCall ) Value is treated as a native JavaScript function . This increases performance because there are no
automatic argument and return value type conversions ( which involves reflect ) . Attempting to use
the function as a constructor will result in a TypeError . Note : implementations must not retain and use references
to FunctionCall . Arguments after the function returns .
func ( FunctionCall , * Runtime ) Value is treated as above , except the * Runtime is also passed as a parameter .
func ( ConstructorCall ) * Object is treated as a native constructor , allowing to use it with the new
operator :
func MyObject ( call goja . ConstructorCall ) * goja . Object {
// call.This contains the newly created object as per http://www.ecma-international.org/ecma-262/5.1/index.html#sec-13.2.2
// call.Arguments contain arguments passed to the function
call . This . Set ( "method" , method )
//...
// If return value is a non-nil *Object, it will be used instead of call.This
// This way it is possible to return a Go struct or a map converted
// into goja.Value using ToValue(), however in this case
// instanceof will not work as expected, unless you set the prototype:
//
// instance := &myCustomStruct{}
// instanceValue := vm.ToValue(instance).(*Object)
// instanceValue.SetPrototype(call.This.Prototype())
// return instanceValue
return nil
}
runtime . Set ( "MyObject" , MyObject )
Then it can be used in JS as follows :
var o = new MyObject ( arg ) ;
var o1 = MyObject ( arg ) ; // same thing
o instanceof MyObject && o1 instanceof MyObject ; // true
When a native constructor is called directly ( without the new operator ) its behavior depends on
this value : if it ' s an Object , it is passed through , otherwise a new one is created exactly as
if it was called with the new operator . In either case call . NewTarget will be nil .
func ( ConstructorCall , * Runtime ) * Object is treated as above , except the * Runtime is also passed as a parameter .
Any other Go function is wrapped so that the arguments are automatically converted into the required Go types and the
return value is converted to a JavaScript value ( using this method ) . If conversion is not possible , a TypeError is
thrown .
Functions with multiple return values return an Array . If the last return value is an ` error ` it is not returned but
converted into a JS exception . If the error is * Exception , it is thrown as is , otherwise it ' s wrapped in a GoEerror .
Note that if there are exactly two return values and the last is an ` error ` , the function returns the first value as is ,
not an Array .
# Structs
Structs are converted to Object - like values . Fields and methods are available as properties , their values are
results of this method ( ToValue ( ) ) applied to the corresponding Go value .
Field properties are writable and non - configurable . Method properties are non - writable and non - configurable .
Attempt to define a new property or delete an existing property will fail ( throw in strict mode ) unless it ' s a Symbol
property . Symbol properties only exist in the wrapper and do not affect the underlying Go value .
Note that because a wrapper is created every time a property is accessed it may lead to unexpected results such as this :
type Field struct {
}
type S struct {
Field * Field
}
var s = S {
Field : & Field { } ,
}
vm := New ( )
vm . Set ( "s" , & s )
res , err := vm . RunString ( `
var sym = Symbol ( 66 ) ;
var field1 = s . Field ;
field1 [ sym ] = true ;
var field2 = s . Field ;
field1 == = field2 ; // true, because the equality operation compares the wrapped values, not the wrappers
field1 [ sym ] == = true ; // true
field2 [ sym ] == = undefined ; // also true
` )
The same applies to values from maps and slices as well .
# Handling of time . Time
time . Time does not get special treatment and therefore is converted just like any other ` struct ` providing access to
all its methods . This is done deliberately instead of converting it to a ` Date ` because these two types are not fully
compatible : ` time.Time ` includes zone , whereas JS ` Date ` doesn ' t . Doing the conversion implicitly therefore would
result in a loss of information .
If you need to convert it to a ` Date ` , it can be done either in JS :
var d = new Date ( goval . UnixNano ( ) / 1e6 ) ;
... or in Go :
now := time . Now ( )
vm := New ( )
val , err := vm . New ( vm . Get ( "Date" ) . ToObject ( vm ) , vm . ToValue ( now . UnixNano ( ) / 1e6 ) )
if err != nil {
...
}
vm . Set ( "d" , val )
Note that Value . Export ( ) for a ` Date ` value returns time . Time in local timezone .
# Maps
Maps with string , integer , or float key types are converted into host objects that largely behave like a JavaScript Object .
One noticeable difference is that the key order is not stable , as with maps in Go .
Keys are converted to strings following the fmt . Sprintf ( "%v" ) convention .
# Maps with methods
If a map type has at least one method defined , the properties of the resulting Object represent methods , not map keys .
This is because in JavaScript there is no distinction between ' object . key ` and ` object [ key ] ` , unlike Go .
If access to the map values is required , it can be achieved by defining another method or , if it ' s not possible , by
defining an external getter function .
# Slices
Slices are converted into host objects that behave largely like JavaScript Array . It has the appropriate
prototype and all the usual methods should work . There is , however , a caveat : converted Arrays may not contain holes
( because Go slices cannot ) . This means that hasOwnProperty ( n ) always returns ` true ` if n < length . Deleting an item with
an index < length will set it to a zero value ( but the property will remain ) . Nil slice elements are be converted to
` null ` . Accessing an element beyond ` length ` returns ` undefined ` . Also see the warning above about passing slices as
values ( as opposed to pointers ) .
# Arrays
Arrays are converted similarly to slices , except the resulting Arrays are not resizable ( and therefore the ' length '
property is non - writable ) .
Any other type is converted to a generic reflect based host object . Depending on the underlying type it behaves similar
to a Number , String , Boolean or Object .
Note that the underlying type is not lost , calling Export ( ) returns the original Go value . This applies to all
reflect based types .
* /
func ( r * Runtime ) ToValue ( i interface { } ) Value {
return r . toValue ( i , reflect . Value { } )
}
func ( r * Runtime ) toValue ( i interface { } , origValue reflect . Value ) Value {
switch i := i . ( type ) {
case nil :
return _null
case * Object :
if i == nil || i . self == nil {
return _null
}
if i . runtime != nil && i . runtime != r {
panic ( r . NewTypeError ( "Illegal runtime transition of an Object" ) )
}
return i
case valueContainer :
return i . toValue ( r )
case Value :
return i
case string :
if len ( i ) <= 16 {
if u := unistring . Scan ( i ) ; u != nil {
return & importedString { s : i , u : u , scanned : true }
}
return asciiString ( i )
}
return & importedString { s : i }
case bool :
if i {
return valueTrue
} else {
return valueFalse
}
case func ( FunctionCall ) Value :
name := unistring . NewFromString ( runtime . FuncForPC ( reflect . ValueOf ( i ) . Pointer ( ) ) . Name ( ) )
return r . newNativeFunc ( i , name , 0 )
case func ( FunctionCall , * Runtime ) Value :
name := unistring . NewFromString ( runtime . FuncForPC ( reflect . ValueOf ( i ) . Pointer ( ) ) . Name ( ) )
return r . newNativeFunc ( func ( call FunctionCall ) Value {
return i ( call , r )
} , name , 0 )
case func ( ConstructorCall ) * Object :
name := unistring . NewFromString ( runtime . FuncForPC ( reflect . ValueOf ( i ) . Pointer ( ) ) . Name ( ) )
return r . newNativeConstructor ( i , name , 0 )
case func ( ConstructorCall , * Runtime ) * Object :
name := unistring . NewFromString ( runtime . FuncForPC ( reflect . ValueOf ( i ) . Pointer ( ) ) . Name ( ) )
return r . newNativeConstructor ( func ( call ConstructorCall ) * Object {
return i ( call , r )
} , name , 0 )
case int :
return intToValue ( int64 ( i ) )
case int8 :
return intToValue ( int64 ( i ) )
case int16 :
return intToValue ( int64 ( i ) )
case int32 :
return intToValue ( int64 ( i ) )
case int64 :
return intToValue ( i )
case uint :
if uint64 ( i ) <= math . MaxInt64 {
return intToValue ( int64 ( i ) )
} else {
return floatToValue ( float64 ( i ) )
}
case uint8 :
return intToValue ( int64 ( i ) )
case uint16 :
return intToValue ( int64 ( i ) )
case uint32 :
return intToValue ( int64 ( i ) )
case uint64 :
if i <= math . MaxInt64 {
return intToValue ( int64 ( i ) )
}
return floatToValue ( float64 ( i ) )
case float32 :
return floatToValue ( float64 ( i ) )
case float64 :
return floatToValue ( i )
case * big . Int :
return ( * valueBigInt ) ( new ( big . Int ) . Set ( i ) )
case map [ string ] interface { } :
if i == nil {
return _null
}
obj := & Object { runtime : r }
m := & objectGoMapSimple {
baseObject : baseObject {
val : obj ,
extensible : true ,
} ,
data : i ,
}
obj . self = m
m . init ( )
return obj
case [ ] interface { } :
return r . newObjectGoSlice ( & i , false ) . val
case * [ ] interface { } :
if i == nil {
return _null
}
return r . newObjectGoSlice ( i , true ) . val
}
if ! origValue . IsValid ( ) {
origValue = reflect . ValueOf ( i )
}
value := origValue
for value . Kind ( ) == reflect . Ptr {
value = value . Elem ( )
}
if ! value . IsValid ( ) {
return _null
}
switch value . Kind ( ) {
case reflect . Map :
if value . Type ( ) . NumMethod ( ) == 0 {
switch value . Type ( ) . Key ( ) . Kind ( ) {
case reflect . String , reflect . Int , reflect . Int8 , reflect . Int16 , reflect . Int32 , reflect . Int64 ,
reflect . Uint , reflect . Uint8 , reflect . Uint16 , reflect . Uint32 , reflect . Uint64 ,
reflect . Float64 , reflect . Float32 :
obj := & Object { runtime : r }
m := & objectGoMapReflect {
objectGoReflect : objectGoReflect {
baseObject : baseObject {
val : obj ,
extensible : true ,
} ,
origValue : origValue ,
fieldsValue : value ,
} ,
}
m . init ( )
obj . self = m
return obj
}
}
case reflect . Array :
obj := & Object { runtime : r }
a := & objectGoArrayReflect {
objectGoReflect : objectGoReflect {
baseObject : baseObject {
val : obj ,
} ,
origValue : origValue ,
fieldsValue : value ,
} ,
}
a . init ( )
obj . self = a
return obj
case reflect . Slice :
obj := & Object { runtime : r }
a := & objectGoSliceReflect {
objectGoArrayReflect : objectGoArrayReflect {
objectGoReflect : objectGoReflect {
baseObject : baseObject {
val : obj ,
} ,
origValue : origValue ,
fieldsValue : value ,
} ,
} ,
}
a . init ( )
obj . self = a
return obj
case reflect . Func :
return r . newWrappedFunc ( value )
}
obj := & Object { runtime : r }
o := & objectGoReflect {
baseObject : baseObject {
val : obj ,
} ,
origValue : origValue ,
fieldsValue : value ,
}
obj . self = o
o . init ( )
return obj
}
func ( r * Runtime ) wrapReflectFunc ( value reflect . Value ) func ( FunctionCall ) Value {
return func ( call FunctionCall ) Value {
typ := value . Type ( )
nargs := typ . NumIn ( )
var in [ ] reflect . Value
if l := len ( call . Arguments ) ; l < nargs {
// fill missing arguments with zero values
n := nargs
if typ . IsVariadic ( ) {
n --
}
in = make ( [ ] reflect . Value , n )
for i := l ; i < n ; i ++ {
in [ i ] = reflect . Zero ( typ . In ( i ) )
}
} else {
if l > nargs && ! typ . IsVariadic ( ) {
l = nargs
}
in = make ( [ ] reflect . Value , l )
}
for i , a := range call . Arguments {
var t reflect . Type
n := i
if n >= nargs - 1 && typ . IsVariadic ( ) {
if n > nargs - 1 {
n = nargs - 1
}
t = typ . In ( n ) . Elem ( )
} else if n > nargs - 1 { // ignore extra arguments
break
} else {
t = typ . In ( n )
}
v := reflect . New ( t ) . Elem ( )
err := r . toReflectValue ( a , v , & objectExportCtx { } )
if err != nil {
panic ( r . NewTypeError ( "could not convert function call parameter %d: %v" , i , err ) )
}
in [ i ] = v
}
out := value . Call ( in )
if len ( out ) == 0 {
return _undefined
}
if last := out [ len ( out ) - 1 ] ; last . Type ( ) == reflectTypeError {
if ! last . IsNil ( ) {
err := last . Interface ( ) . ( error )
if _ , ok := err . ( * Exception ) ; ok {
panic ( err )
}
if isUncatchableException ( err ) {
panic ( err )
}
panic ( r . NewGoError ( err ) )
}
out = out [ : len ( out ) - 1 ]
}
switch len ( out ) {
case 0 :
return _undefined
case 1 :
return r . ToValue ( out [ 0 ] . Interface ( ) )
default :
s := make ( [ ] interface { } , len ( out ) )
for i , v := range out {
s [ i ] = v . Interface ( )
}
return r . ToValue ( s )
}
}
}
func ( r * Runtime ) toReflectValue ( v Value , dst reflect . Value , ctx * objectExportCtx ) error {
typ := dst . Type ( )
if typ == typeValue {
dst . Set ( reflect . ValueOf ( v ) )
return nil
}
if typ == typeObject {
if obj , ok := v . ( * Object ) ; ok {
dst . Set ( reflect . ValueOf ( obj ) )
return nil
}
}
if typ == typeCallable {
if fn , ok := AssertFunction ( v ) ; ok {
dst . Set ( reflect . ValueOf ( fn ) )
return nil
}
}
et := v . ExportType ( )
if et == nil || et == reflectTypeNil {
dst . Set ( reflect . Zero ( typ ) )
return nil
}
kind := typ . Kind ( )
for i := 0 ; ; i ++ {
if et . AssignableTo ( typ ) {
ev := reflect . ValueOf ( exportValue ( v , ctx ) )
for ; i > 0 ; i -- {
ev = ev . Elem ( )
}
dst . Set ( ev )
return nil
}
expKind := et . Kind ( )
if expKind == kind && et . ConvertibleTo ( typ ) || expKind == reflect . String && typ == typeBytes {
ev := reflect . ValueOf ( exportValue ( v , ctx ) )
for ; i > 0 ; i -- {
ev = ev . Elem ( )
}
dst . Set ( ev . Convert ( typ ) )
return nil
}
if expKind == reflect . Ptr {
et = et . Elem ( )
} else {
break
}
}
if typ == typeTime {
if obj , ok := v . ( * Object ) ; ok {
if d , ok := obj . self . ( * dateObject ) ; ok {
dst . Set ( reflect . ValueOf ( d . time ( ) ) )
return nil
}
}
if et . Kind ( ) == reflect . String {
tme , ok := dateParse ( v . String ( ) )
if ! ok {
return fmt . Errorf ( "could not convert string %v to %v" , v , typ )
}
dst . Set ( reflect . ValueOf ( tme ) )
return nil
}
}
switch kind {
case reflect . String :
dst . Set ( reflect . ValueOf ( v . String ( ) ) . Convert ( typ ) )
return nil
case reflect . Bool :
dst . Set ( reflect . ValueOf ( v . ToBoolean ( ) ) . Convert ( typ ) )
return nil
case reflect . Int :
dst . Set ( reflect . ValueOf ( toInt ( v ) ) . Convert ( typ ) )
return nil
case reflect . Int64 :
dst . Set ( reflect . ValueOf ( toInt64 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Int32 :
dst . Set ( reflect . ValueOf ( toInt32 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Int16 :
dst . Set ( reflect . ValueOf ( toInt16 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Int8 :
dst . Set ( reflect . ValueOf ( toInt8 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Uint :
dst . Set ( reflect . ValueOf ( toUint ( v ) ) . Convert ( typ ) )
return nil
case reflect . Uint64 :
dst . Set ( reflect . ValueOf ( toUint64 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Uint32 :
dst . Set ( reflect . ValueOf ( toUint32 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Uint16 :
dst . Set ( reflect . ValueOf ( toUint16 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Uint8 :
dst . Set ( reflect . ValueOf ( toUint8 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Float64 :
dst . Set ( reflect . ValueOf ( v . ToFloat ( ) ) . Convert ( typ ) )
return nil
case reflect . Float32 :
dst . Set ( reflect . ValueOf ( toFloat32 ( v ) ) . Convert ( typ ) )
return nil
case reflect . Slice , reflect . Array :
if o , ok := v . ( * Object ) ; ok {
if v , exists := ctx . getTyped ( o , typ ) ; exists {
dst . Set ( reflect . ValueOf ( v ) )
return nil
}
return o . self . exportToArrayOrSlice ( dst , typ , ctx )
}
case reflect . Map :
if o , ok := v . ( * Object ) ; ok {
if v , exists := ctx . getTyped ( o , typ ) ; exists {
dst . Set ( reflect . ValueOf ( v ) )
return nil
}
return o . self . exportToMap ( dst , typ , ctx )
}
case reflect . Struct :
if o , ok := v . ( * Object ) ; ok {
t := reflect . PtrTo ( typ )
if v , exists := ctx . getTyped ( o , t ) ; exists {
dst . Set ( reflect . ValueOf ( v ) . Elem ( ) )
return nil
}
s := dst
ctx . putTyped ( o , t , s . Addr ( ) . Interface ( ) )
for i := 0 ; i < typ . NumField ( ) ; i ++ {
field := typ . Field ( i )
if ast . IsExported ( field . Name ) {
name := field . Name
if r . fieldNameMapper != nil {
name = r . fieldNameMapper . FieldName ( typ , field )
}
var v Value
if field . Anonymous {
v = o
} else {
v = o . self . getStr ( unistring . NewFromString ( name ) , nil )
}
if v != nil {
err := r . toReflectValue ( v , s . Field ( i ) , ctx )
if err != nil {
return fmt . Errorf ( "could not convert struct value %v to %v for field %s: %w" , v , field . Type , field . Name , err )
}
}
}
}
return nil
}
case reflect . Func :
if fn , ok := AssertFunction ( v ) ; ok {
dst . Set ( reflect . MakeFunc ( typ , r . wrapJSFunc ( fn , typ ) ) )
return nil
}
case reflect . Ptr :
if o , ok := v . ( * Object ) ; ok {
if v , exists := ctx . getTyped ( o , typ ) ; exists {
dst . Set ( reflect . ValueOf ( v ) )
return nil
}
}
if dst . IsNil ( ) {
dst . Set ( reflect . New ( typ . Elem ( ) ) )
}
return r . toReflectValue ( v , dst . Elem ( ) , ctx )
}
return fmt . Errorf ( "could not convert %v to %v" , v , typ )
}
func ( r * Runtime ) wrapJSFunc ( fn Callable , typ reflect . Type ) func ( args [ ] reflect . Value ) ( results [ ] reflect . Value ) {
return func ( args [ ] reflect . Value ) ( results [ ] reflect . Value ) {
var jsArgs [ ] Value
if len ( args ) > 0 {
if typ . IsVariadic ( ) {
varArg := args [ len ( args ) - 1 ]
args = args [ : len ( args ) - 1 ]
jsArgs = make ( [ ] Value , 0 , len ( args ) + varArg . Len ( ) )
for _ , arg := range args {
jsArgs = append ( jsArgs , r . ToValue ( arg . Interface ( ) ) )
}
for i := 0 ; i < varArg . Len ( ) ; i ++ {
jsArgs = append ( jsArgs , r . ToValue ( varArg . Index ( i ) . Interface ( ) ) )
}
} else {
jsArgs = make ( [ ] Value , len ( args ) )
for i , arg := range args {
jsArgs [ i ] = r . ToValue ( arg . Interface ( ) )
}
}
}
numOut := typ . NumOut ( )
results = make ( [ ] reflect . Value , numOut )
res , err := fn ( _undefined , jsArgs ... )
if err == nil {
if numOut > 0 {
v := reflect . New ( typ . Out ( 0 ) ) . Elem ( )
err = r . toReflectValue ( res , v , & objectExportCtx { } )
if err == nil {
results [ 0 ] = v
}
}
}
if err != nil {
if numOut > 0 && typ . Out ( numOut - 1 ) == reflectTypeError {
if ex , ok := err . ( * Exception ) ; ok {
if exo , ok := ex . val . ( * Object ) ; ok {
if v := exo . self . getStr ( "value" , nil ) ; v != nil {
if v . ExportType ( ) . AssignableTo ( reflectTypeError ) {
err = v . Export ( ) . ( error )
}
}
}
}
results [ numOut - 1 ] = reflect . ValueOf ( err ) . Convert ( typ . Out ( numOut - 1 ) )
} else {
panic ( err )
}
}
for i , v := range results {
if ! v . IsValid ( ) {
results [ i ] = reflect . Zero ( typ . Out ( i ) )
}
}
return
}
}
// ExportTo converts a JavaScript value into the specified Go value. The second parameter must be a non-nil pointer.
// Returns error if conversion is not possible.
//
// Notes on specific cases:
//
// # Empty interface
//
// Exporting to an interface{} results in a value of the same type as Value.Export() would produce.
//
// # Numeric types
//
// Exporting to numeric types uses the standard ECMAScript conversion operations, same as used when assigning
// values to non-clamped typed array items, e.g. https://262.ecma-international.org/#sec-toint32.
//
// # Functions
//
// Exporting to a 'func' creates a strictly typed 'gateway' into an ES function which can be called from Go.
// The arguments are converted into ES values using Runtime.ToValue(). If the func has no return values,
// the return value is ignored. If the func has exactly one return value, it is converted to the appropriate
// type using ExportTo(). If the last return value is 'error', exceptions are caught and returned as *Exception
// (instances of GoError are unwrapped, i.e. their 'value' is returned instead). In all other cases exceptions
// result in a panic. Any extra return values are zeroed.
//
// 'this' value will always be set to 'undefined'.
//
// For a more low-level mechanism see AssertFunction().
//
// # Map types
//
// An ES Map can be exported into a Go map type. If any exported key value is non-hashable, the operation panics
// (as reflect.Value.SetMapIndex() would). Symbol.iterator is ignored.
//
// Exporting an ES Set into a map type results in the map being populated with (element) -> (zero value) key/value
// pairs. If any value is non-hashable, the operation panics (as reflect.Value.SetMapIndex() would).
// Symbol.iterator is ignored.
//
// Any other Object populates the map with own enumerable non-symbol properties.
//
// # Slice types
//
// Exporting an ES Set into a slice type results in its elements being exported.
//
// Exporting any Object that implements the iterable protocol (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterable_protocol)
// into a slice type results in the slice being populated with the results of the iteration.
//
// Array is treated as iterable (i.e. overwriting Symbol.iterator affects the result).
//
// If an object has a 'length' property and is not a function it is treated as array-like. The resulting slice
// will contain obj[0], ... obj[length-1].
//
// ArrayBuffer and ArrayBuffer-backed types (i.e. typed arrays and DataView) can be exported into []byte. The result
// is backed by the original data, no copy is performed.
//
// For any other Object an error is returned.
//
// # Array types
//
// Anything that can be exported to a slice type can also be exported to an array type, as long as the lengths
// match. If they do not, an error is returned.
//
// # Proxy
//
// Proxy objects are treated the same way as if they were accessed from ES code in regard to their properties
// (such as 'length' or [Symbol.iterator]). This means exporting them to slice types works, however
// exporting a proxied Map into a map type does not produce its contents, because the Proxy is not recognised
// as a Map. Same applies to a proxied Set.
func ( r * Runtime ) ExportTo ( v Value , target interface { } ) error {
tval := reflect . ValueOf ( target )
if tval . Kind ( ) != reflect . Ptr || tval . IsNil ( ) {
return errors . New ( "target must be a non-nil pointer" )
}
return r . toReflectValue ( v , tval . Elem ( ) , & objectExportCtx { } )
}
// GlobalObject returns the global object.
func ( r * Runtime ) GlobalObject ( ) * Object {
return r . globalObject
}
// Set the specified variable in the global context.
// Equivalent to running "name = value" in non-strict mode.
// The value is first converted using ToValue().
// Note, this is not the same as GlobalObject().Set(name, value),
// because if a global lexical binding (let or const) exists, it is set instead.
func ( r * Runtime ) Set ( name string , value interface { } ) error {
return r . try ( func ( ) {
name := unistring . NewFromString ( name )
v := r . ToValue ( value )
if ref := r . global . stash . getRefByName ( name , false ) ; ref != nil {
ref . set ( v )
} else {
r . globalObject . self . setOwnStr ( name , v , true )
}
} )
}
// Get the specified variable in the global context.
// Equivalent to dereferencing a variable by name in non-strict mode. If variable is not defined returns nil.
// Note, this is not the same as GlobalObject().Get(name),
// because if a global lexical binding (let or const) exists, it is used instead.
// This method will panic with an *Exception if a JavaScript exception is thrown in the process. Use Runtime.Try to catch these.
func ( r * Runtime ) Get ( name string ) Value {
n := unistring . NewFromString ( name )
if v , exists := r . global . stash . getByName ( n ) ; exists {
return v
} else {
return r . globalObject . self . getStr ( n , nil )
}
}
// SetRandSource sets random source for this Runtime. If not called, the default math/rand is used.
func ( r * Runtime ) SetRandSource ( source RandSource ) {
r . rand = source
}
// SetTimeSource sets the current time source for this Runtime.
// If not called, the default time.Now() is used.
func ( r * Runtime ) SetTimeSource ( now Now ) {
r . now = now
}
// SetParserOptions sets parser options to be used by RunString, RunScript and eval() within the code.
func ( r * Runtime ) SetParserOptions ( opts ... parser . Option ) {
r . parserOptions = opts
}
// SetMaxCallStackSize sets the maximum function call depth. When exceeded, a *StackOverflowError is thrown and
// returned by RunProgram or by a Callable call. This is useful to prevent memory exhaustion caused by an
// infinite recursion. The default value is math.MaxInt32.
// This method (as the rest of the Set* methods) is not safe for concurrent use and may only be called
// from the vm goroutine or when the vm is not running.
func ( r * Runtime ) SetMaxCallStackSize ( size int ) {
r . vm . maxCallStackSize = size
}
// New is an equivalent of the 'new' operator allowing to call it directly from Go.
func ( r * Runtime ) New ( construct Value , args ... Value ) ( o * Object , err error ) {
err = r . try ( func ( ) {
o = r . builtin_new ( r . toObject ( construct ) , args )
} )
return
}
// Callable represents a JavaScript function that can be called from Go.
type Callable func ( this Value , args ... Value ) ( Value , error )
// AssertFunction checks if the Value is a function and returns a Callable.
// Note, for classes this returns a callable and a 'true', however calling it will always result in a TypeError.
// For classes use AssertConstructor().
func AssertFunction ( v Value ) ( Callable , bool ) {
if obj , ok := v . ( * Object ) ; ok {
if f , ok := obj . self . assertCallable ( ) ; ok {
return func ( this Value , args ... Value ) ( ret Value , err error ) {
err = obj . runtime . runWrapped ( func ( ) {
ret = f ( FunctionCall {
This : this ,
Arguments : args ,
} )
} )
return
} , true
}
}
return nil , false
}
// Constructor is a type that can be used to call constructors. The first argument (newTarget) can be nil
// which sets it to the constructor function itself.
type Constructor func ( newTarget * Object , args ... Value ) ( * Object , error )
// AssertConstructor checks if the Value is a constructor and returns a Constructor.
func AssertConstructor ( v Value ) ( Constructor , bool ) {
if obj , ok := v . ( * Object ) ; ok {
if ctor := obj . self . assertConstructor ( ) ; ctor != nil {
return func ( newTarget * Object , args ... Value ) ( ret * Object , err error ) {
err = obj . runtime . runWrapped ( func ( ) {
ret = ctor ( args , newTarget )
} )
return
} , true
}
}
return nil , false
}
func ( r * Runtime ) runWrapped ( f func ( ) ) ( err error ) {
defer func ( ) {
if x := recover ( ) ; x != nil {
if ex := asUncatchableException ( x ) ; ex != nil {
err = ex
if len ( r . vm . callStack ) == 0 {
r . leaveAbrupt ( )
}
} else {
panic ( x )
}
}
} ( )
ex := r . vm . try ( f )
if ex != nil {
err = ex
}
if len ( r . vm . callStack ) == 0 {
r . leave ( )
} else {
r . vm . clearStack ( )
}
return
}
// IsUndefined returns true if the supplied Value is undefined. Note, it checks against the real undefined, not
// against the global object's 'undefined' property.
func IsUndefined ( v Value ) bool {
return v == _undefined
}
// IsNull returns true if the supplied Value is null.
func IsNull ( v Value ) bool {
return v == _null
}
// IsNaN returns true if the supplied value is NaN.
func IsNaN ( v Value ) bool {
f , ok := v . ( valueFloat )
return ok && math . IsNaN ( float64 ( f ) )
}
// IsInfinity returns true if the supplied is (+/-)Infinity
func IsInfinity ( v Value ) bool {
return v == _positiveInf || v == _negativeInf
}
// Undefined returns JS undefined value. Note if global 'undefined' property is changed this still returns the original value.
func Undefined ( ) Value {
return _undefined
}
// Null returns JS null value.
func Null ( ) Value {
return _null
}
// NaN returns a JS NaN value.
func NaN ( ) Value {
return _NaN
}
// PositiveInf returns a JS +Inf value.
func PositiveInf ( ) Value {
return _positiveInf
}
// NegativeInf returns a JS -Inf value.
func NegativeInf ( ) Value {
return _negativeInf
}
func tryFunc ( f func ( ) ) ( ret interface { } ) {
defer func ( ) {
ret = recover ( )
} ( )
f ( )
return
}
// Try runs a given function catching and returning any JS exception. Use this method to run any code
// that may throw exceptions (such as Object.Get, Object.String, Object.ToInteger, Object.Export, Runtime.Get, Runtime.InstanceOf, etc.)
// outside the Runtime execution context (i.e. when calling directly from Go, not from a JS function implemented in Go).
func ( r * Runtime ) Try ( f func ( ) ) * Exception {
return r . vm . try ( f )
}
func ( r * Runtime ) try ( f func ( ) ) error {
if ex := r . vm . try ( f ) ; ex != nil {
return ex
}
return nil
}
func ( r * Runtime ) toObject ( v Value , args ... interface { } ) * Object {
if obj , ok := v . ( * Object ) ; ok {
return obj
}
if len ( args ) > 0 {
panic ( r . NewTypeError ( args ... ) )
} else {
var s string
if v == nil {
s = "undefined"
} else {
s = v . String ( )
}
panic ( r . NewTypeError ( "Value is not an object: %s" , s ) )
}
}
func ( r * Runtime ) speciesConstructor ( o , defaultConstructor * Object ) func ( args [ ] Value , newTarget * Object ) * Object {
c := o . self . getStr ( "constructor" , nil )
if c != nil && c != _undefined {
c = r . toObject ( c ) . self . getSym ( SymSpecies , nil )
}
if c == nil || c == _undefined || c == _null {
c = defaultConstructor
}
return r . toConstructor ( c )
}
func ( r * Runtime ) speciesConstructorObj ( o , defaultConstructor * Object ) * Object {
c := o . self . getStr ( "constructor" , nil )
if c != nil && c != _undefined {
c = r . toObject ( c ) . self . getSym ( SymSpecies , nil )
}
if c == nil || c == _undefined || c == _null {
return defaultConstructor
}
obj := r . toObject ( c )
if obj . self . assertConstructor ( ) == nil {
panic ( r . NewTypeError ( "Value is not a constructor" ) )
}
return obj
}
func ( r * Runtime ) returnThis ( call FunctionCall ) Value {
return call . This
}
func createDataProperty ( o * Object , p Value , v Value ) {
o . defineOwnProperty ( p , PropertyDescriptor {
Writable : FLAG_TRUE ,
Enumerable : FLAG_TRUE ,
Configurable : FLAG_TRUE ,
Value : v ,
} , false )
}
func createDataPropertyOrThrow ( o * Object , p Value , v Value ) {
o . defineOwnProperty ( p , PropertyDescriptor {
Writable : FLAG_TRUE ,
Enumerable : FLAG_TRUE ,
Configurable : FLAG_TRUE ,
Value : v ,
} , true )
}
func toPropertyKey ( key Value ) Value {
return key . ToString ( )
}
func ( r * Runtime ) getVStr ( v Value , p unistring . String ) Value {
o := v . ToObject ( r )
return o . self . getStr ( p , v )
}
func ( r * Runtime ) getV ( v Value , p Value ) Value {
o := v . ToObject ( r )
return o . get ( p , v )
}
type iteratorRecord struct {
iterator * Object
next func ( FunctionCall ) Value
}
func ( r * Runtime ) getIterator ( obj Value , method func ( FunctionCall ) Value ) * iteratorRecord {
if method == nil {
method = toMethod ( r . getV ( obj , SymIterator ) )
if method == nil {
panic ( r . NewTypeError ( "object is not iterable" ) )
}
}
iter := r . toObject ( method ( FunctionCall {
This : obj ,
} ) )
var next func ( FunctionCall ) Value
if obj , ok := iter . self . getStr ( "next" , nil ) . ( * Object ) ; ok {
if call , ok := obj . self . assertCallable ( ) ; ok {
next = call
}
}
return & iteratorRecord {
iterator : iter ,
next : next ,
}
}
func iteratorComplete ( iterResult * Object ) bool {
return nilSafe ( iterResult . self . getStr ( "done" , nil ) ) . ToBoolean ( )
}
func iteratorValue ( iterResult * Object ) Value {
return nilSafe ( iterResult . self . getStr ( "value" , nil ) )
}
func ( ir * iteratorRecord ) iterate ( step func ( Value ) ) {
r := ir . iterator . runtime
for {
if ir . next == nil {
panic ( r . NewTypeError ( "iterator.next is missing or not a function" ) )
}
res := r . toObject ( ir . next ( FunctionCall { This : ir . iterator } ) )
if iteratorComplete ( res ) {
break
}
value := iteratorValue ( res )
ret := tryFunc ( func ( ) {
step ( value )
} )
if ret != nil {
_ = tryFunc ( func ( ) {
ir . returnIter ( )
} )
panic ( ret )
}
}
}
func ( ir * iteratorRecord ) step ( ) ( value Value , ex * Exception ) {
r := ir . iterator . runtime
ex = r . vm . try ( func ( ) {
res := r . toObject ( ir . next ( FunctionCall { This : ir . iterator } ) )
done := iteratorComplete ( res )
if ! done {
value = iteratorValue ( res )
} else {
ir . close ( )
}
} )
return
}
func ( ir * iteratorRecord ) returnIter ( ) {
if ir . iterator == nil {
return
}
retMethod := toMethod ( ir . iterator . self . getStr ( "return" , nil ) )
if retMethod != nil {
ir . iterator . runtime . toObject ( retMethod ( FunctionCall { This : ir . iterator } ) )
}
ir . iterator = nil
ir . next = nil
}
func ( ir * iteratorRecord ) close ( ) {
ir . iterator = nil
ir . next = nil
}
// ForOf is a Go equivalent of for-of loop. The function panics if an exception is thrown at any point
// while iterating, including if the supplied value is not iterable
// (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterable_protocol).
// When using outside of Runtime.Run (i.e. when calling directly from Go code, not from a JS function implemented
// in Go) it must be enclosed in Try. See the example.
func ( r * Runtime ) ForOf ( iterable Value , step func ( curValue Value ) ( continueIteration bool ) ) {
iter := r . getIterator ( iterable , nil )
for {
value , ex := iter . step ( )
if ex != nil {
panic ( ex )
}
if value != nil {
var continueIteration bool
ex := r . vm . try ( func ( ) {
continueIteration = step ( value )
} )
if ex != nil {
iter . returnIter ( )
panic ( ex )
}
if ! continueIteration {
iter . returnIter ( )
break
}
} else {
break
}
}
}
func ( r * Runtime ) createIterResultObject ( value Value , done bool ) Value {
o := r . NewObject ( )
o . self . setOwnStr ( "value" , value , false )
o . self . setOwnStr ( "done" , r . toBoolean ( done ) , false )
return o
}
func ( r * Runtime ) getHash ( ) * maphash . Hash {
if r . hash == nil {
r . hash = & maphash . Hash { }
}
return r . hash
}
// called when the top level function returns normally (i.e. control is passed outside the Runtime).
func ( r * Runtime ) leave ( ) {
var jobs [ ] func ( )
for len ( r . jobQueue ) > 0 {
jobs , r . jobQueue = r . jobQueue , jobs [ : 0 ]
for _ , job := range jobs {
job ( )
}
}
r . jobQueue = nil
r . vm . stack = nil
}
// called when the top level function returns (i.e. control is passed outside the Runtime) but it was due to an interrupt
func ( r * Runtime ) leaveAbrupt ( ) {
r . jobQueue = nil
r . ClearInterrupt ( )
}
func nilSafe ( v Value ) Value {
if v != nil {
return v
}
return _undefined
}
func isArray ( object * Object ) bool {
self := object . self
if proxy , ok := self . ( * proxyObject ) ; ok {
if proxy . target == nil {
panic ( typeError ( "Cannot perform 'IsArray' on a proxy that has been revoked" ) )
}
return isArray ( proxy . target )
}
switch self . className ( ) {
case classArray :
return true
default :
return false
}
}
func isRegexp ( v Value ) bool {
if o , ok := v . ( * Object ) ; ok {
matcher := o . self . getSym ( SymMatch , nil )
if matcher != nil && matcher != _undefined {
return matcher . ToBoolean ( )
}
_ , reg := o . self . ( * regexpObject )
return reg
}
return false
}
func limitCallArgs ( call FunctionCall , n int ) FunctionCall {
if len ( call . Arguments ) > n {
return FunctionCall { This : call . This , Arguments : call . Arguments [ : n ] }
} else {
return call
}
}
func shrinkCap ( newSize , oldCap int ) int {
if oldCap > 8 {
if cap := oldCap / 2 ; cap >= newSize {
return cap
}
}
return oldCap
}
func growCap ( newSize , oldSize , oldCap int ) int {
// Use the same algorithm as in runtime.growSlice
doublecap := oldCap + oldCap
if newSize > doublecap {
return newSize
} else {
if oldSize < 1024 {
return doublecap
} else {
cap := oldCap
// Check 0 < cap to detect overflow
// and prevent an infinite loop.
for 0 < cap && cap < newSize {
cap += cap / 4
}
// Return the requested cap when
// the calculation overflowed.
if cap <= 0 {
return newSize
}
return cap
}
}
}
func ( r * Runtime ) genId ( ) ( ret uint64 ) {
if r . hash == nil {
h := r . getHash ( )
r . idSeq = h . Sum64 ( )
}
if r . idSeq == 0 {
r . idSeq = 1
}
ret = r . idSeq
r . idSeq ++
return
}
func ( r * Runtime ) setGlobal ( name unistring . String , v Value , strict bool ) {
if ref := r . global . stash . getRefByName ( name , strict ) ; ref != nil {
ref . set ( v )
} else {
o := r . globalObject . self
if strict {
if o . hasOwnPropertyStr ( name ) {
o . setOwnStr ( name , v , true )
} else {
r . throwReferenceError ( name )
}
} else {
o . setOwnStr ( name , v , false )
}
}
}
func ( r * Runtime ) trackPromiseRejection ( p * Promise , operation PromiseRejectionOperation ) {
if r . promiseRejectionTracker != nil {
r . promiseRejectionTracker ( p , operation )
}
}
func ( r * Runtime ) callJobCallback ( job * jobCallback , this Value , args ... Value ) Value {
return job . callback ( FunctionCall { This : this , Arguments : args } )
}
func ( r * Runtime ) invoke ( v Value , p unistring . String , args ... Value ) Value {
o := v . ToObject ( r )
return r . toCallable ( o . self . getStr ( p , nil ) ) ( FunctionCall { This : v , Arguments : args } )
}
func ( r * Runtime ) iterableToList ( iterable Value , method func ( FunctionCall ) Value ) [ ] Value {
iter := r . getIterator ( iterable , method )
var values [ ] Value
iter . iterate ( func ( item Value ) {
values = append ( values , item )
} )
return values
}
func ( r * Runtime ) putSpeciesReturnThis ( o objectImpl ) {
o . _putSym ( SymSpecies , & valueProperty {
getterFunc : r . newNativeFunc ( r . returnThis , "get [Symbol.species]" , 0 ) ,
accessor : true ,
configurable : true ,
} )
}
func strToArrayIdx ( s unistring . String ) uint32 {
if s == "" {
return math . MaxUint32
}
l := len ( s )
if s [ 0 ] == '0' {
if l == 1 {
return 0
}
return math . MaxUint32
}
var n uint32
if l < 10 {
// guaranteed not to overflow
for i := 0 ; i < len ( s ) ; i ++ {
c := s [ i ]
if c < '0' || c > '9' {
return math . MaxUint32
}
n = n * 10 + uint32 ( c - '0' )
}
return n
}
if l > 10 {
// guaranteed to overflow
return math . MaxUint32
}
c9 := s [ 9 ]
if c9 < '0' || c9 > '9' {
return math . MaxUint32
}
for i := 0 ; i < 9 ; i ++ {
c := s [ i ]
if c < '0' || c > '9' {
return math . MaxUint32
}
n = n * 10 + uint32 ( c - '0' )
}
if n >= math . MaxUint32 / 10 + 1 {
return math . MaxUint32
}
n *= 10
n1 := n + uint32 ( c9 - '0' )
if n1 < n {
return math . MaxUint32
}
return n1
}
func strToInt32 ( s unistring . String ) ( int32 , bool ) {
if s == "" {
return - 1 , false
}
neg := s [ 0 ] == '-'
if neg {
s = s [ 1 : ]
}
l := len ( s )
if s [ 0 ] == '0' {
if l == 1 {
return 0 , ! neg
}
return - 1 , false
}
var n uint32
if l < 10 {
// guaranteed not to overflow
for i := 0 ; i < len ( s ) ; i ++ {
c := s [ i ]
if c < '0' || c > '9' {
return - 1 , false
}
n = n * 10 + uint32 ( c - '0' )
}
} else if l > 10 {
// guaranteed to overflow
return - 1 , false
} else {
c9 := s [ 9 ]
if c9 >= '0' {
if ! neg && c9 > '7' || c9 > '8' {
// guaranteed to overflow
return - 1 , false
}
for i := 0 ; i < 9 ; i ++ {
c := s [ i ]
if c < '0' || c > '9' {
return - 1 , false
}
n = n * 10 + uint32 ( c - '0' )
}
if n >= math . MaxInt32 / 10 + 1 {
// valid number, but it overflows integer
return 0 , false
}
n = n * 10 + uint32 ( c9 - '0' )
} else {
return - 1 , false
}
}
if neg {
return int32 ( - n ) , true
}
return int32 ( n ) , true
}
func strToInt64 ( s unistring . String ) ( int64 , bool ) {
if s == "" {
return - 1 , false
}
neg := s [ 0 ] == '-'
if neg {
s = s [ 1 : ]
}
l := len ( s )
if s [ 0 ] == '0' {
if l == 1 {
return 0 , ! neg
}
return - 1 , false
}
var n uint64
if l < 19 {
// guaranteed not to overflow
for i := 0 ; i < len ( s ) ; i ++ {
c := s [ i ]
if c < '0' || c > '9' {
return - 1 , false
}
n = n * 10 + uint64 ( c - '0' )
}
} else if l > 19 {
// guaranteed to overflow
return - 1 , false
} else {
c18 := s [ 18 ]
if c18 >= '0' {
if ! neg && c18 > '7' || c18 > '8' {
// guaranteed to overflow
return - 1 , false
}
for i := 0 ; i < 18 ; i ++ {
c := s [ i ]
if c < '0' || c > '9' {
return - 1 , false
}
n = n * 10 + uint64 ( c - '0' )
}
if n >= math . MaxInt64 / 10 + 1 {
// valid number, but it overflows integer
return 0 , false
}
n = n * 10 + uint64 ( c18 - '0' )
} else {
return - 1 , false
}
}
if neg {
return int64 ( - n ) , true
}
return int64 ( n ) , true
}
func strToInt ( s unistring . String ) ( int , bool ) {
if bits . UintSize == 32 {
n , ok := strToInt32 ( s )
return int ( n ) , ok
}
n , ok := strToInt64 ( s )
return int ( n ) , ok
}
// Attempts to convert a string into a canonical integer.
// On success returns (number, true).
// If it was a canonical number, but not an integer returns (0, false). This includes -0 and overflows.
// In all other cases returns (-1, false).
// See https://262.ecma-international.org/#sec-canonicalnumericindexstring
func strToIntNum ( s unistring . String ) ( int , bool ) {
n , ok := strToInt64 ( s )
if n == 0 {
return 0 , ok
}
if ok && n >= - maxInt && n <= maxInt {
if bits . UintSize == 32 {
if n > math . MaxInt32 || n < math . MinInt32 {
return 0 , false
}
}
return int ( n ) , true
}
str := stringValueFromRaw ( s )
if str . ToNumber ( ) . toString ( ) . SameAs ( str ) {
return 0 , false
}
return - 1 , false
}
func strToGoIdx ( s unistring . String ) int {
if n , ok := strToInt ( s ) ; ok {
return n
}
return - 1
}
func strToIdx64 ( s unistring . String ) int64 {
if n , ok := strToInt64 ( s ) ; ok {
return n
}
return - 1
}
func assertCallable ( v Value ) ( func ( FunctionCall ) Value , bool ) {
if obj , ok := v . ( * Object ) ; ok {
return obj . self . assertCallable ( )
}
return nil , false
}
// InstanceOf is an equivalent of "left instanceof right".
// This method will panic with an *Exception if a JavaScript exception is thrown in the process. Use Runtime.Try to catch these.
func ( r * Runtime ) InstanceOf ( left Value , right * Object ) ( res bool ) {
return instanceOfOperator ( left , right )
}
func ( r * Runtime ) methodProp ( f func ( FunctionCall ) Value , name unistring . String , nArgs int ) Value {
return valueProp ( r . newNativeFunc ( f , name , nArgs ) , true , false , true )
}
func ( r * Runtime ) getPrototypeFromCtor ( newTarget , defCtor , defProto * Object ) * Object {
if newTarget == defCtor {
return defProto
}
proto := newTarget . self . getStr ( "prototype" , nil )
if obj , ok := proto . ( * Object ) ; ok {
return obj
}
return defProto
}