IgniteUI / igniteui-webcomponents / 28843926680

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Build Type

push

github

Committed by web-flow

Commit Message

refactor(tree): rewrite internals for performance, fix scroll/animaton regressions (#2283)

* refactor(tree): rewrite internals for performance, fix scroll/animation regressions

Rearchitect igc-tree/igc-tree-item's internal wiring while preserving the
public API (properties, attributes, events, methods, CSS parts/custom
properties) and existing behaviors.

- Replace `closest('igc-tree')` DOM-traversal wiring with a `@lit/context`
  provider/consumer (new tree.context.ts) so items resolve their owning tree
  synchronously without querying the DOM.
- Replace `querySelectorAll`-based child/descendant resolution with native
  light-DOM `.children` traversal; drop support for tree items wrapped in
  intermediate elements (e.g. `<div>`) in favor of direct nesting.
- Rewrite keyboard navigation on top of the shared `key-bindings` controller
  instead of a manual keydown switch statement; compute the
  navigable/visible item set on demand instead of eagerly caching it,
  removing the O(n²) recompute-on-every-mount root cause of prior sluggishness.
- Fix a real algorithmic issue in child/descendant collection: replace
  recursive `flatMap` + spread concatenation (quadratic for deeply nested
  trees) with a single-pass accumulator.
- Add `contain: layout` to the tree container and each tree-item host to
  scope reflow cost, smoothing out the expand/collapse height animation
  without reintroducing the compositing/scroll-jank risk that ruled out
  `content-visibility` for this component.
- Fix keyboard-navigation scroll lag: focus-driven scrollIntoView now scrolls
  instantly instead of `smooth`, so holding an arrow key no longer causes the
  visible scroll position to fall behind the actual focused/active item.
- Normalize all private members in tree-item.ts to the project's `_`-prefix
  convention.

Test suite: adapted tree-utils.spec.ts/tree.spec.ts fixtures for the
dropped wrapper-element support; all other specs unchanged and passing
against the new implem... (continued)

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459 of 464 new or added lines in 3 files covered. (98.92%)

1 existing line in 1 file now uncovered.

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