The array of items to virtualize.

Compared by reference: a mutation in place (data.push(...)) causes no update. Assign a new array instead. The igcDataRequest flow also expects a new array.

Estimated item size in pixels, used before an item is measured in the DOM. After the first render of an item, the engine replaces the estimate with the measured size.

A function that renders each item in the virtual scroll list. Receives a VirtualScrollItemContext with the item data, its index, and the total count. Without it, nothing is rendered.

Items are measured by their border box, so margins accumulate as drift down the list. Use padding on the item, or a gap on a wrapper, instead.

Only the current window is in the DOM, so assistive technology cannot infer an item's position from the markup. Templates that render a role with set semantics (option, listitem, row, ...) should map the context's index and count onto aria-posinset and aria-setsize.

Scroll orientation of the virtual scroll.

Number of extra items to render beyond the visible area of the viewport. Higher values reduce blank flashes during fast scrolling but can lower performance.

The tagName read-only property of the Element interface returns the tag name of the element on which it's called.

MDN Reference