120 lines
2.9 KiB
TypeScript
120 lines
2.9 KiB
TypeScript
// #docplaster
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// #docregion
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import {Component, AfterContentChecked, AfterContentInit, ContentChild} from '@angular/core';
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import {LoggerService} from './logger.service';
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//////////////////
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@Component({
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selector: 'my-child',
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template: '<input [(ngModel)]="hero">'
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})
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export class ChildComponent {
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hero = 'Magneta';
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}
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//////////////////////
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@Component({
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selector: 'after-content',
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// #docregion template
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template: `
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<div>-- projected content begins --</div>
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<ng-content></ng-content>
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<div>-- projected content ends --</div>`
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// #enddocregion template
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+ `
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<p *ngIf="comment" class="comment">
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{{comment}}
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</p>
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`
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})
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// #docregion hooks
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export class AfterContentComponent implements AfterContentChecked, AfterContentInit {
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private _prevHero = '';
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comment = '';
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// Query for a CONTENT child of type `ChildComponent`
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@ContentChild(ChildComponent) contentChild: ChildComponent;
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// #enddocregion hooks
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constructor(private _logger: LoggerService) {
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this._logIt('AfterContent constructor');
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}
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// #docregion hooks
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ngAfterContentInit() {
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// viewChild is set after the view has been initialized
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this._logIt('AfterContentInit');
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this._doSomething();
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}
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ngAfterContentChecked() {
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// viewChild is updated after the view has been checked
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if (this._prevHero === this.contentChild.hero) {
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this._logIt('AfterContentChecked (no change)');
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} else {
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this._prevHero = this.contentChild.hero;
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this._logIt('AfterContentChecked');
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this._doSomething();
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}
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}
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// #enddocregion hooks
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// #docregion do-something
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// This surrogate for real business logic sets the `comment`
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private _doSomething() {
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this.comment = this.contentChild.hero.length > 10 ? 'That\'s a long name' : '';
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}
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private _logIt(method: string) {
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let vc = this.contentChild;
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let message = `${method}: ${vc ? vc.hero : 'no'} child view`;
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this._logger.log(message);
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}
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// #docregion hooks
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// ...
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}
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// #enddocregion hooks
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//////////////
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@Component({
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selector: 'after-content-parent',
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template: `
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<div class="parent">
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<h2>AfterContent</h2>
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<div *ngIf="show">` +
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// #docregion parent-template
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`<after-content>
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<my-child></my-child>
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</after-content>`
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// #enddocregion parent-template
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+ `</div>
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<h4>-- AfterContent Logs --</h4>
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<p><button (click)="reset()">Reset</button></p>
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<div *ngFor="let msg of logs">{{msg}}</div>
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</div>
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`,
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styles: ['.parent {background: burlywood}'],
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providers: [LoggerService],
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directives: [AfterContentComponent, ChildComponent]
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})
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export class AfterContentParentComponent {
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logs: string[];
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show = true;
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constructor(logger: LoggerService) {
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this.logs = logger.logs;
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}
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reset() {
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this.logs.length = 0;
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// quickly remove and reload AfterContentComponent which recreates it
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this.show = false;
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setTimeout(() => this.show = true, 0);
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}
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}
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