Function directiveFactory

packages/upgrade/src/common/src/downgrade_component.ts:102–250

(
    $compile: ICompileService,
    $injector: IInjectorService,
    $parse: IParseService,
  )

  selectors?: string[];
}): any /* angular.IInjectable */ {
  const directiveFactory: IAnnotatedFunction = function (
    $compile: ICompileService,
    $injector: IInjectorService,
    $parse: IParseService,
  ): IDirective {
    const unsafelyOverwriteSignalInputs =
      (info as {unsafelyOverwriteSignalInputs?: boolean}).unsafelyOverwriteSignalInputs ?? false;
    // When using `downgradeModule()`, we need to handle certain things specially. For example:
    // - We always need to attach the component view to the `ApplicationRef` for it to be
    //   dirty-checked.
    // - We need to ensure callbacks to Angular APIs (e.g. change detection) are run inside the
    //   Angular zone.
    //   NOTE: This is not needed, when using `UpgradeModule`, because `$digest()` will be run
    //         inside the Angular zone (except if explicitly escaped, in which case we shouldn't
    //         force it back in).
    const isNgUpgradeLite = getUpgradeAppType($injector) === UpgradeAppType.Lite;
    const wrapCallback: <T>(cb: () => T) => typeof cb = !isNgUpgradeLite
      ? (cb) => cb
      : (cb) => () => (NgZone.isInAngularZone() ? cb() : ngZone.run(cb));
    let ngZone: NgZone;

    // When downgrading multiple modules, special handling is needed wrt injectors.
    const hasMultipleDowngradedModules = isNgUpgradeLite && getDowngradedModuleCount($injector) > 1;

    return {
      restrict: 'E',
      terminal: true,
      require: [REQUIRE_INJECTOR, REQUIRE_NG_MODEL],
      // Controller needs to be set so that `angular-component-router.js` (from beta Angular 2)
      // configuration properties can be made available. See:
      // See G3: javascript/angular2/angular1_router_lib.js
      // https://github.com/angular/angular.js/blob/47bf11ee94664367a26ed8c91b9b586d3dd420f5/src/ng/compile.js#L1670-L1691.
      controller: function () {},
      link: (scope: IScope, element: IAugmentedJQuery, attrs: IAttributes, required: any[]) => {
        // We might have to compile the contents asynchronously, because this might have been
        // triggered by `UpgradeNg1ComponentAdapterBuilder`, before the Angular templates have
        // been compiled.

        const ngModel: INgModelController = required[1];
        const parentInjector: Injector | Thenable<Injector> | undefined = required[0];
        let moduleInjector: Injector | Thenable<Injector> | undefined = undefined;
        let ranAsync = false;

        if (!parentInjector || hasMultipleDowngradedModules) {
          const downgradedModule = info.downgradedModule || '';
          const lazyModuleRefKey = `${LAZY_MODULE_REF}${downgradedModule}`;
          const attemptedAction = `instantiating component '${getTypeName(info.component)}'`;

          validateInjectionKey($injector, downgradedModule, lazyModuleRefKey, attemptedAction);

          const lazyModuleRef = $injector.get(lazyModuleRefKey) as LazyModuleRef;
          moduleInjector = lazyModuleRef.injector ?? lazyModuleRef.promise;
        }

        // Notes:
        //
        // There are two injectors: `finalModuleInjector` and `finalParentInjector` (they might be
        // the same instance, but that is irrelevant):