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UpgradeComponent

directive

A helper class that allows an AngularJS component to be used from Angular.

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NgModules

Description

Part of the upgrade/static library for hybrid upgrade apps that support AOT compilation.

This helper class should be used as a base class for creating Angular directives that wrap AngularJS components that need to be "upgraded".

Examples

Let's assume that you have an AngularJS component called ng1Hero that needs to be made available in Angular templates.

// This AngularJS component will be "upgraded" to be used in Angular
ng1AppModule.component('ng1Hero', {
  bindings: {hero: '<', onRemove: '&'},
  transclude: true,
  template: `<div class="title" ng-transclude></div>
             <h2>{{ $ctrl.hero.name }}</h2>
             <p>{{ $ctrl.hero.description }}</p>
             <button ng-click="$ctrl.onRemove()">Remove</button>`
});

We must create a Directive that will make this AngularJS component available inside Angular templates.

// This Angular directive will act as an interface to the "upgraded" AngularJS component
@Directive({selector: 'ng1-hero'})
export class Ng1HeroComponentWrapper extends UpgradeComponent {
  // The names of the input and output properties here must match the names of the
  // `<` and `&` bindings in the AngularJS component that is being wrapped
  @Input() hero!: Hero;
  @Output() onRemove!: EventEmitter<void>;

  constructor(elementRef: ElementRef, injector: Injector) {
    // We must pass the name of the directive as used by AngularJS to the super
    super('ng1Hero', elementRef, injector);
  }
}

In this example you can see that we must derive from the UpgradeComponent base class but also provide an `@Directive` decorator. This is because the AOT compiler requires that this information is statically available at compile time.

Note that we must do the following:

  • specify the directive's selector (ng1-hero)
  • specify all inputs and outputs that the AngularJS component expects
  • derive from UpgradeComponent
  • call the base class from the constructor, passing

    • the AngularJS name of the component (ng1Hero)
    • the ElementRef and Injector for the component wrapper

Methods

ngOnInit()

Parameters

There are no parameters.

ngOnChanges(changes: SimpleChanges)

Parameters
changes SimpleChanges

ngDoCheck()

Parameters

There are no parameters.

ngOnDestroy()

Parameters

There are no parameters.

© 2010–2020 Google, Inc.
Licensed under the Creative Commons Attribution License 4.0.
https://angular.io/api/upgrade/static/UpgradeComponent