class ApplicationRef {
/** @internal */
constructor(_zone, _console, _injector, _exceptionHandler, _componentFactoryResolver, _initStatus) {
this._zone = _zone;
this._console = _console;
this._injector = _injector;
this._exceptionHandler = _exceptionHandler;
this._componentFactoryResolver = _componentFactoryResolver;
this._initStatus = _initStatus;
/** @internal */
this._bootstrapListeners = [];
this._views = [];
this._runningTick = false;
this._enforceNoNewChanges = false;
this._stable = true;
/**
* Get a list of component types registered to this application.
* This list is populated even before the component is created.
*/
this.componentTypes = [];
/**
* Get a list of components registered to this application.
*/
this.components = [];
this._enforceNoNewChanges = isDevMode();
this._zone.onMicrotaskEmpty.subscribe({
next: () => {
this._zone.run(() => {
this.tick();
});
}
});
tick方法的实现会调用视图view的detectChange方法：/**
* Invoke this method to explicitly process change detection and its side-effects.
*
* In development mode, `tick()` also performs a second change detection cycle to ensure that no
* further changes are detected. If additional changes are picked up during this second cycle,
* bindings in the app have side-effects that cannot be resolved in a single change detection
* pass.
* In this case, Angular throws an error, since an Angular application can only have one change
* detection pass during which all change detection must complete.
*/
tick() {
if (this._runningTick) {
throw new Error('ApplicationRef.tick is called recursively');
}
try {
this._runningTick = true;
for (let view of this._views) {
view.detectChanges();
}
if (this._enforceNoNewChanges) {
for (let view of this._views) {
view.checkNoChanges();
}
}
}
catch (e) {
// Attention: Don't rethrow as it could cancel subscriptions to Observables!
this._zone.runOutsideAngular(() => this._exceptionHandler.handleError(e));
}
finally {
this._runningTick = false;
}
}
