Function locateDirectiveOrProvider

packages/core/src/render3/di.ts:685–721

(
  tNode: TNode,
  tView: TView,
  token: ProviderToken<T> | string,
  canAccessViewProviders: boolean,
  isHostSpecialCase: boolean | number,
)

 * @returns Index of a found directive or provider, or null when none found.
 */
export function locateDirectiveOrProvider<T>(
  tNode: TNode,
  tView: TView,
  token: ProviderToken<T> | string,
  canAccessViewProviders: boolean,
  isHostSpecialCase: boolean | number,
): number | null {
  const nodeProviderIndexes = tNode.providerIndexes;
  const tInjectables = tView.data;

  const injectablesStart = nodeProviderIndexes & TNodeProviderIndexes.ProvidersStartIndexMask;
  const directivesStart = tNode.directiveStart;
  const directiveEnd = tNode.directiveEnd;
  const cptViewProvidersCount =
    nodeProviderIndexes >> TNodeProviderIndexes.CptViewProvidersCountShift;
  const startingIndex = canAccessViewProviders
    ? injectablesStart
    : injectablesStart + cptViewProvidersCount;
  // When the host special case applies, only the viewProviders and the component are visible
  const endIndex = isHostSpecialCase ? injectablesStart + cptViewProvidersCount : directiveEnd;
  for (let i = startingIndex; i < endIndex; i++) {
    const providerTokenOrDef = tInjectables[i] as ProviderToken<any> | DirectiveDef<any> | string;
    if (
      (i < directivesStart && token === providerTokenOrDef) ||
      (i >= directivesStart && (providerTokenOrDef as DirectiveDef<any>).type === token)
    ) {
      return i;
    }
  }
  if (isHostSpecialCase) {
    const dirDef = tInjectables[directivesStart] as DirectiveDef<any>;
    if (dirDef && isComponentDef(dirDef) && dirDef.type === token) {
      return directivesStart;
    }
  }
  return null;
}

/**
 * Used in ngDevMode to keep the injection path in case of cycles in DI.