Function stylingFirstUpdatePass

packages/core/src/render3/instructions/styling.ts:324–351

* Collects the necessary information to insert the binding into a linked list of style bindings * using `insertTStylingBinding`. * * @param tView `TView` where the binding linked list will be stored. * @param tStylingKey Property/key of the binding. * @param bindingIndex Index of binding associ

(
  tView: TView,
  tStylingKey: TStylingKey,
  bindingIndex: number,
  isClassBased: boolean,
)

 * @param isClassBased `true` if `class` change (`false` if `style`)
 */
function stylingFirstUpdatePass(
  tView: TView,
  tStylingKey: TStylingKey,
  bindingIndex: number,
  isClassBased: boolean,
): void {
  ngDevMode && assertFirstUpdatePass(tView);
  const tData = tView.data;
  if (tData[bindingIndex + 1] === null) {
    // The above check is necessary because we don't clear first update pass until first successful
    // (no exception) template execution. This prevents the styling instruction from double adding
    // itself to the list.
    // `getSelectedIndex()` should be here (rather than in instruction) so that it is guarded by the
    // if so as not to read unnecessarily.
    const tNode = tData[getSelectedIndex()] as TNode;
    ngDevMode && assertDefined(tNode, 'TNode expected');
    const isHostBindings = isInHostBindings(tView, bindingIndex);
    if (hasStylingInputShadow(tNode, isClassBased) && tStylingKey === null && !isHostBindings) {
      // `tStylingKey === null` implies that we are either `[style]` or `[class]` binding.
      // If there is a directive which uses `@Input('style')` or `@Input('class')` than
      // we need to neutralize this binding since that directive is shadowing it.
      // We turn this into a noop by setting the key to `false`
      tStylingKey = false;
    }
    tStylingKey = wrapInStaticStylingKey(tData, tNode, tStylingKey, isClassBased);
    insertTStylingBinding(tData, tNode, tStylingKey, bindingIndex, isHostBindings, isClassBased);
  }
}

/**
 * Adds static styling information to the binding if applicable.