2026-07-12 02:03:28 +08:00
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name: VirtualScroll
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2026-07-12 13:00:02 +08:00
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purpose: Variable-height virtual scrolling utility used by List and DataGrid.
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2026-07-12 02:03:28 +08:00
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factory:
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signature: VirtualScroll(options)
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options:
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itemHeight: Optional fixed initial item height.
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methods:
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reset: Initialize a new list and return its first render window.
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init: Measure initial data and invoke refresh callback.
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update: Measure one rendered item.
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calc: Return paddings, renderedList, and listStartIndex for current scroll position.
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rules:
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- Treat this as an internal UI utility unless implementing a virtualized component.
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- Call update after each rendered row can be measured.
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2026-07-18 11:44:16 +08:00
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examples:
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basic: |
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const virtual = VirtualScroll({ itemHeight: 40 })
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virtual.reset(rows, container)
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virtual.init(rows, () => refresh())
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const view = virtual.calc(container, rows)
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tests:
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- ../components/base/List.test.html
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- ../components/data/DataGrid.test.html
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