Function setupInitialInputs

packages/core/src/render3/view/directives.ts:366–429

* Sets up the initialInputData for a node and stores it in the template's static storage * so subsequent template invocations don't have to recalculate it. * * initialInputData is an array containing values that need to be set as input properties * for directives on this node, but only once on c

(tNode: TNode, directiveIndex: number, isHostDirective: boolean)

 * @param directiveIndex Index of the directive that is currently being processed.
 */
function setupInitialInputs(tNode: TNode, directiveIndex: number, isHostDirective: boolean): void {
  const {attrs, inputs, hostDirectiveInputs} = tNode;

  if (
    attrs === null ||
    (!isHostDirective && inputs === null) ||
    (isHostDirective && hostDirectiveInputs === null) ||
    // Do not use unbound attributes as inputs to structural directives, since structural
    // directive inputs can only be set using microsyntax (e.g. `<div *dir="exp">`).
    isInlineTemplate(tNode)
  ) {
    tNode.initialInputs ??= [];
    tNode.initialInputs.push(null);
    return;
  }

  let inputsToStore: InitialInputs | null = null;
  let i = 0;
  while (i < attrs.length) {
    const attrName = attrs[i];
    if (attrName === AttributeMarker.NamespaceURI) {
      // We do not allow inputs on namespaced attributes.
      i += 4;
      continue;
    } else if (attrName === AttributeMarker.ProjectAs) {
      // Skip over the `ngProjectAs` value.
      i += 2;
      continue;
    } else if (typeof attrName === 'number') {
      // If we hit any other attribute markers, we're done anyway. None of those are valid inputs.
      break;
    }

    if (!isHostDirective && inputs!.hasOwnProperty(attrName as string)) {
      // Find the input's public name from the input store. Note that we can be found easier
      // through the directive def, but we want to do it using the inputs store so that it can
      // account for host directive aliases.
      const inputConfig = inputs![attrName as string];

      for (const index of inputConfig) {
        if (index === directiveIndex) {
          inputsToStore ??= [];
          inputsToStore.push(attrName as string, attrs[i + 1] as string);
          // A directive can't have multiple inputs with the same name so we can break here.
          break;
        }
      }
    } else if (isHostDirective && hostDirectiveInputs!.hasOwnProperty(attrName as string)) {
      const config = hostDirectiveInputs![attrName as string];
      for (let j = 0; j < config.length; j += 2) {
        if (config[j] === directiveIndex) {
          inputsToStore ??= [];
          inputsToStore.push(config[j + 1] as string, attrs[i + 1] as string);
          break;
        }
      }
    }