angular-docs-cn/packages/core/test/acceptance/content_spec.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {CommonModule} from '@angular/common';
import {ChangeDetectorRef, Component, Directive, TemplateRef, ViewChild, ViewContainerRef} from '@angular/core';
import {Input} from '@angular/core/src/metadata';
import {TestBed} from '@angular/core/testing';
import {By} from '@angular/platform-browser';
import {expect} from '@angular/platform-browser/testing/src/matchers';

describe('projection', () => {
  function getElementHtml(element: HTMLElement) {
    return element.innerHTML.replace(/<!--(\W|\w)*?-->/g, '')
        .replace(/\sng-reflect-\S*="[^"]*"/g, '');
  }

  it('should project content', () => {
    @Component({selector: 'child', template: `<div><ng-content></ng-content></div>`})
    class Child {
    }

    @Component({selector: 'parent', template: '<child>content</child>'})
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML).toBe(`<child><div>content</div></child>`);
  });

  it('should project content when <ng-content> is at a template root', () => {
    @Component({
      selector: 'child',
      template: '<ng-content></ng-content>',
    })
    class Child {
    }

    @Component({
      selector: 'parent',
      template: '<child>content</child>',
    })
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML).toBe(`<child>content</child>`);
  });

  it('should project content with siblings', () => {
    @Component({selector: 'child', template: '<ng-content></ng-content>'})
    class Child {
    }

    @Component({selector: 'parent', template: `<child>before<div>content</div>after</child>`})
    class Parent {
    }


    TestBed.configureTestingModule({declarations: [Parent, Child]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML).toBe(`<child>before<div>content</div>after</child>`);
  });

  it('should be able to re-project content', () => {
    @Component({selector: 'grand-child', template: `<div><ng-content></ng-content></div>`})
    class GrandChild {
    }

    @Component(
        {selector: 'child', template: `<grand-child><ng-content></ng-content></grand-child>`})
    class Child {
    }

    @Component({
      selector: 'parent',
      template: `<child><b>Hello</b>World!</child>`,
    })
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child, GrandChild]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML)
        .toBe('<child><grand-child><div><b>Hello</b>World!</div></grand-child></child>');
  });

  it('should project components', () => {
    @Component({
      selector: 'child',
      template: `<div><ng-content></ng-content></div>`,
    })
    class Child {
    }

    @Component({
      selector: 'projected-comp',
      template: 'content',
    })
    class ProjectedComp {
    }

    @Component({selector: 'parent', template: `<child><projected-comp></projected-comp></child>`})
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child, ProjectedComp]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML)
        .toBe('<child><div><projected-comp>content</projected-comp></div></child>');
  });

  it('should project components that have their own projection', () => {
    @Component({selector: 'child', template: `<div><ng-content></ng-content></div>`})
    class Child {
    }

    @Component({selector: 'projected-comp', template: `<p><ng-content></ng-content></p>`})
    class ProjectedComp {
    }

    @Component({
      selector: 'parent',
      template: `
        <child>
          <projected-comp><div>Some content</div>Other content</projected-comp>
        </child>`,
    })
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child, ProjectedComp]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML)
        .toBe(
            `<child><div><projected-comp><p><div>Some content</div>Other content</p></projected-comp></div></child>`);
  });

  it('should project with multiple instances of a component with projection', () => {
    @Component({selector: 'child', template: `<div><ng-content></ng-content></div>`})
    class Child {
    }

    @Component({selector: 'projected-comp', template: `Before<ng-content></ng-content>After`})
    class ProjectedComp {
    }

    @Component({
      selector: 'parent',
      template: `
        <child>
          <projected-comp><div>A</div><p>123</p></projected-comp>
          <projected-comp><div>B</div><p>456</p></projected-comp>
        </child>`,
    })
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child, ProjectedComp]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML)
        .toBe(
            '<child><div>' +
            '<projected-comp>Before<div>A</div><p>123</p>After</projected-comp>' +
            '<projected-comp>Before<div>B</div><p>456</p>After</projected-comp>' +
            '</div></child>');
  });

  it('should re-project with multiple instances of a component with projection', () => {
    @Component({selector: 'child', template: `<div><ng-content></ng-content></div>`})
    class Child {
    }

    @Component({selector: 'projected-comp', template: `Before<ng-content></ng-content>After`})
    class ProjectedComp {
    }

    @Component({
      selector: 'parent',
      template: `
        <child>
          <projected-comp><div>A</div><ng-content></ng-content><p>123</p></projected-comp>
          <projected-comp><div>B</div><p>456</p></projected-comp>
        </child>`,
    })
    class Parent {
    }

    @Component({
      selector: 'app',
      template: `
        <parent>**ABC**</parent>
        <parent>**DEF**</parent>
     `,
    })
    class App {
    }

    TestBed.configureTestingModule({declarations: [App, Parent, Child, ProjectedComp]});
    const fixture = TestBed.createComponent(App);
    fixture.detectChanges();

    expect(fixture.nativeElement.innerHTML)
        .toBe(
            '<parent><child><div>' +
            '<projected-comp>Before<div>A</div>**ABC**<p>123</p>After</projected-comp>' +
            '<projected-comp>Before<div>B</div><p>456</p>After</projected-comp>' +
            '</div></child></parent>' +
            '<parent><child><div>' +
            '<projected-comp>Before<div>A</div>**DEF**<p>123</p>After</projected-comp>' +
            '<projected-comp>Before<div>B</div><p>456</p>After</projected-comp>' +
            '</div></child></parent>');
  });

  it('should project into dynamic views (with createEmbeddedView)', () => {
    @Component({
      selector: 'child',
      template: `Before-<ng-template [ngIf]="showing"><ng-content></ng-content></ng-template>-After`
    })
    class Child {
      showing = false;
    }

    @Component({selector: 'parent', template: `<child><div>A</div>Some text</child>`})
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child], imports: [CommonModule]});

    const fixture = TestBed.createComponent(Parent);
    const childDebugEl = fixture.debugElement.query(By.directive(Child));
    const childInstance = childDebugEl.injector.get(Child);
    const childElement = childDebugEl.nativeElement as HTMLElement;

    childInstance.showing = true;
    fixture.detectChanges();

    expect(getElementHtml(childElement)).toBe(`Before-<div>A</div>Some text-After`);

    childInstance.showing = false;
    fixture.detectChanges();

    expect(getElementHtml(childElement)).toBe(`Before--After`);

    childInstance.showing = true;
    fixture.detectChanges();
    expect(getElementHtml(childElement)).toBe(`Before-<div>A</div>Some text-After`);
  });

  it('should project into dynamic views with specific selectors', () => {
    @Component({
      selector: 'child',
      template: `
        <ng-content></ng-content>
        Before-
        <ng-template [ngIf]="showing">
          <ng-content select="div"></ng-content>
        </ng-template>
        -After`
    })
    class Child {
      showing = false;
    }

    @Component({
      selector: 'parent',
      template: `
        <child>
          <div>A</div>
          <span>B</span>
        </child>
      `
    })
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child], imports: [CommonModule]});

    const fixture = TestBed.createComponent(Parent);
    const childDebugEl = fixture.debugElement.query(By.directive(Child));
    const childInstance = childDebugEl.injector.get(Child);

    childInstance.showing = true;
    fixture.detectChanges();

    expect(getElementHtml(fixture.nativeElement))
        .toBe('<child><span>B</span> Before- <div>A</div> -After</child>');

    childInstance.showing = false;
    fixture.detectChanges();
    expect(getElementHtml(fixture.nativeElement))
        .toBe('<child><span>B</span> Before-  -After</child>');

    childInstance.showing = true;
    fixture.detectChanges();
    expect(getElementHtml(fixture.nativeElement))
        .toBe('<child><span>B</span> Before- <div>A</div> -After</child>');
  });

  it('should project if <ng-content> is in a template that has different declaration/insertion points',
     () => {
       @Component(
           {selector: 'comp', template: `<ng-template><ng-content></ng-content></ng-template>`})
       class Comp {
         @ViewChild(TemplateRef, {static: true}) template !: TemplateRef<any>;
       }

       @Directive({selector: '[trigger]'})
       class Trigger {
         @Input() trigger!: Comp;

         constructor(public vcr: ViewContainerRef) {}

         open() {
           this.vcr.createEmbeddedView(this.trigger.template);
         }
       }

       @Component({
         selector: 'parent',
         template: `
        <button [trigger]="comp"></button>
        <comp #comp>Some content</comp>
      `
       })
       class Parent {
       }

       TestBed.configureTestingModule({declarations: [Parent, Trigger, Comp]});

       const fixture = TestBed.createComponent(Parent);
       const trigger = fixture.debugElement.query(By.directive(Trigger)).injector.get(Trigger);
       fixture.detectChanges();

       expect(getElementHtml(fixture.nativeElement)).toBe(`<button></button><comp></comp>`);

       trigger.open();
       expect(getElementHtml(fixture.nativeElement))
           .toBe(`<button></button>Some content<comp></comp>`);
     });

  it('should project nodes into the last ng-content', () => {
    @Component({
      selector: 'child',
      template: `<div><ng-content></ng-content></div>
          <span><ng-content></ng-content></span>`
    })
    class Child {
    }

    @Component({selector: 'parent', template: `<child>content</child>`})
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child], imports: [CommonModule]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(getElementHtml(fixture.nativeElement))
        .toBe('<child><div></div><span>content</span></child>');
  });

  // https://stackblitz.com/edit/angular-ceqmnw?file=src%2Fapp%2Fapp.component.ts
  it('should project nodes into the last ng-content unrolled by ngFor', () => {
    @Component({
      selector: 'child',
      template:
          `<div *ngFor="let item of [1, 2]; let i = index">({{i}}):<ng-content></ng-content></div>`
    })
    class Child {
    }

    @Component({selector: 'parent', template: `<child>content</child>`})
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child], imports: [CommonModule]});
    const fixture = TestBed.createComponent(Parent);
    fixture.detectChanges();

    expect(getElementHtml(fixture.nativeElement))
        .toBe('<child><div>(0):</div><div>(1):content</div></child>');
  });

  it('should handle projected containers inside other containers', () => {
    @Component({selector: 'nested-comp', template: `<div>Child content</div>`})
    class NestedComp {
    }

    @Component({
      selector: 'root-comp',
      template: `<ng-content></ng-content>`,
    })
    class RootComp {
    }

    @Component({
      selector: 'my-app',
      template: `
        <root-comp>
          <ng-container *ngFor="let item of items; last as last">
            <nested-comp *ngIf="!last"></nested-comp>
          </ng-container>
        </root-comp>
      `
    })
    class MyApp {
      items = [1, 2];
    }

    TestBed.configureTestingModule(
        {declarations: [MyApp, RootComp, NestedComp], imports: [CommonModule]});
    const fixture = TestBed.createComponent(MyApp);
    fixture.detectChanges();

    // expecting # of divs to be (items.length - 1), since last element is filtered out by *ngIf,
    // this applies to all other assertions below
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(1);

    fixture.componentInstance.items = [3, 4, 5];
    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(2);

    fixture.componentInstance.items = [6, 7, 8, 9];
    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(3);
  });

  it('should handle projection into element containers at the view root', () => {
    @Component({
      selector: 'root-comp',
      template: `
        <ng-template [ngIf]="show">
          <ng-container>
            <ng-content></ng-content>
          </ng-container>
        </ng-template>`,
    })
    class RootComp {
      @Input() show: boolean = true;
    }

    @Component({
      selector: 'my-app',
      template: `<root-comp [show]="show"><div></div></root-comp>
      `
    })
    class MyApp {
      show = true;
    }

    TestBed.configureTestingModule({declarations: [MyApp, RootComp]});
    const fixture = TestBed.createComponent(MyApp);

    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(1);

    fixture.componentInstance.show = false;
    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(0);
  });

  it('should handle projection of views with element containers at the root', () => {
    @Component({
      selector: 'root-comp',
      template: `<ng-template [ngIf]="show"><ng-content></ng-content></ng-template>`,
    })
    class RootComp {
      @Input() show: boolean = true;
    }

    @Component({
      selector: 'my-app',
      template: `<root-comp [show]="show"><ng-container><div></div></ng-container></root-comp>`
    })
    class MyApp {
      show = true;
    }

    TestBed.configureTestingModule({declarations: [MyApp, RootComp]});
    const fixture = TestBed.createComponent(MyApp);

    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(1);

    fixture.componentInstance.show = false;
    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(0);
  });

  it('should project ng-container at the content root', () => {
    @Component({selector: 'child', template: `<ng-content></ng-content>`})
    class Child {
    }

    @Component({
      selector: 'parent',
      template: `<child>
      <ng-container>
        <ng-container>content</ng-container>
      </ng-container>
    </child>
      `
    })
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child]});
    const fixture = TestBed.createComponent(Parent);

    fixture.detectChanges();
    expect(getElementHtml(fixture.nativeElement)).toBe('<child>content</child>');
  });

  it('should re-project ng-container at the content root', () => {
    @Component({selector: 'grand-child', template: `<ng-content></ng-content>`})
    class GrandChild {
    }

    @Component({
      selector: 'child',
      template: `<grand-child>
      <ng-content></ng-content>
    </grand-child>`
    })
    class Child {
    }

    @Component({
      selector: 'parent',
      template: `<child>
      <ng-container>
        <ng-container>content</ng-container>
      </ng-container>
    </child>
      `
    })
    class Parent {
    }

    TestBed.configureTestingModule({declarations: [Parent, Child, GrandChild]});
    const fixture = TestBed.createComponent(Parent);

    fixture.detectChanges();
    expect(getElementHtml(fixture.nativeElement))
        .toBe('<child><grand-child>content</grand-child></child>');
  });

  it('should handle re-projection at the root of an embedded view', () => {
    @Component({
      selector: 'child-comp',
      template: `<ng-template [ngIf]="show"><ng-content></ng-content></ng-template>`,
    })
    class ChildComp {
      @Input() show: boolean = true;
    }

    @Component({
      selector: 'parent-comp',
      template: `<child-comp [show]="show"><ng-content></ng-content></child-comp>`
    })
    class ParentComp {
      @Input() show: boolean = true;
    }

    @Component(
        {selector: 'my-app', template: `<parent-comp [show]="show"><div></div></parent-comp>`})
    class MyApp {
      show = true;
    }

    TestBed.configureTestingModule({declarations: [MyApp, ParentComp, ChildComp]});
    const fixture = TestBed.createComponent(MyApp);
    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(1);

    fixture.componentInstance.show = false;
    fixture.detectChanges();
    expect(fixture.nativeElement.querySelectorAll('div').length).toBe(0);
  });

  describe('with selectors', () => {
    it('should project nodes using attribute selectors', () => {
      @Component({
        selector: 'child',
        template: `<div id="first"><ng-content select="span[title=toFirst]"></ng-content></div>
          <div id="second"><ng-content select="span[title=toSecond]"></ng-content></div>`,
      })
      class Child {
      }

      @Component({
        selector: 'parent',
        template: `<child><span title="toFirst">1</span><span title="toSecond">2</span></child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<child><div id="first"><span title="toFirst">1</span></div><div id="second"><span title="toSecond">2</span></div></child>');
    });

    it('should project nodes using class selectors', () => {
      @Component({
        selector: 'child',
        template: `<div id="first"><ng-content select="span.toFirst"></ng-content></div>
          <div id="second"><ng-content select="span.toSecond"></ng-content></div>`,
      })
      class Child {
      }

      @Component({
        selector: 'parent',
        template: `<child><span class="toFirst">1</span><span class="toSecond">2</span></child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<child><div id="first"><span class="toFirst">1</span></div><div id="second"><span class="toSecond">2</span></div></child>');
    });

    it('should project nodes using class selectors when element has multiple classes', () => {
      @Component({
        selector: 'child',
        template: `<div id="first"><ng-content select="span.toFirst"></ng-content></div>
          <div id="second"><ng-content select="span.toSecond"></ng-content></div>`
      })
      class Child {
      }

      @Component({
        selector: 'parent',
        template:
            `<child><span class="other toFirst">1</span><span class="noise toSecond">2</span></child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<child><div id="first"><span class="other toFirst">1</span></div><div id="second"><span class="noise toSecond">2</span></div></child>');
    });

    it('should project nodes into the first matching selector', () => {
      @Component({
        selector: 'child',
        template: `<div id="first"><ng-content select="span"></ng-content></div>
          <div id="second"><ng-content select="span.toSecond"></ng-content></div>`
      })
      class Child {
      }

      @Component({
        selector: 'parent',
        template: `<child><span class="toFirst">1</span><span class="toSecond">2</span></child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<child><div id="first"><span class="toFirst">1</span><span class="toSecond">2</span></div><div id="second"></div></child>');
    });

    it('should allow mixing ng-content with and without selectors', () => {
      @Component({
        selector: 'child',
        template: `<div id="first"><ng-content select="span.toFirst"></ng-content></div>
          <div id="second"><ng-content></ng-content></div>`
      })
      class Child {
      }

      @Component({
        selector: 'parent',
        template:
            `<child><span class="toFirst">1</span><span>remaining</span>more remaining</child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<child><div id="first"><span class="toFirst">1</span></div><div id="second"><span>remaining</span>more remaining</div></child>');
    });

    it('should allow mixing ng-content with and without selectors - ng-content first', () => {
      @Component({
        selector: 'child',
        template: `<div id="first"><ng-content></ng-content></div>
          <div id="second"><ng-content select="span.toSecond"></ng-content></div>`
      })
      class Child {
      }

      @Component({
        selector: 'parent',
        template: `<child><span>1</span><span class="toSecond">2</span>remaining</child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<child><div id="first"><span>1</span>remaining</div><div id="second"><span class="toSecond">2</span></div></child>');
    });

    /**
     * Descending into projected content for selector-matching purposes is not supported
     * today: https://plnkr.co/edit/MYQcNfHSTKp9KvbzJWVQ?p=preview
     */
    it('should not descend into re-projected content', () => {
      @Component({
        selector: 'grand-child',
        template: `<ng-content select="span"></ng-content><hr><ng-content></ng-content>`
      })
      class GrandChild {
      }

      @Component({
        selector: 'child',
        template: `<grand-child>
            <ng-content></ng-content>
            <span>in child template</span>
          </grand-child>`
      })
      class Child {
      }

      @Component({selector: 'parent', template: `<child><span>parent content</span></child>`})
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [GrandChild, Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<child><grand-child><span>in child template</span><hr><span>parent content</span></grand-child></child>');
    });

    it('should not descend into re-projected content', () => {
      @Component({
        selector: 'card',
        template:
            `<ng-content select="[card-title]"></ng-content><hr><ng-content select="[card-content]"></ng-content>`
      })
      class Card {
      }

      @Component({
        selector: 'card-with-title',
        template: `<card>
         <h1 card-title>Title</h1>
         <ng-content card-content></ng-content>
       </card>`
      })
      class CardWithTitle {
      }

      @Component({selector: 'parent', template: `<card-with-title>content</card-with-title>`})
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Card, CardWithTitle, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual(
              '<card-with-title><card><h1 card-title="">Title</h1><hr>content</card></card-with-title>');
    });

    it('should not match selectors against node having ngProjectAs attribute', () => {
      @Component({selector: 'child', template: `<ng-content select="div"></ng-content>`})
      class Child {
      }

      @Component({
        selector: 'parent',
        template:
            `<child><div ngProjectAs="span">should not project</div><div>should project</div></child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual('<child><div>should project</div></child>');
    });

    // https://stackblitz.com/edit/angular-psokum?file=src%2Fapp%2Fapp.module.ts
    it('should project nodes where attribute selector matches a binding', () => {
      @Component({
        selector: 'child',
        template: `<ng-content select="[title]"></ng-content>`,
      })
      class Child {
      }

      @Component({
        selector: 'parent',
        template: `<child><span [title]="'Some title'">Has title</span></child>`
      })
      class Parent {
      }

      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual('<child><span title="Some title">Has title</span></child>');
    });

    it('should match selectors against projected containers', () => {
      @Component(
          {selector: 'child', template: `<span><ng-content select="div"></ng-content></span>`})
      class Child {
      }

      @Component({template: `<child><div *ngIf="value">content</div></child>`})
      class Parent {
        value = false;
      }
      TestBed.configureTestingModule({declarations: [Child, Parent]});
      const fixture = TestBed.createComponent(Parent);

      fixture.componentInstance.value = true;
      fixture.detectChanges();

      expect(getElementHtml(fixture.nativeElement))
          .toEqual('<child><span><div>content</div></span></child>');
    });
  });

  it('should handle projected containers inside other containers', () => {
    @Component({
      selector: 'child-comp',  //
      template: '<ng-content></ng-content>'
    })
    class ChildComp {
    }

    @Component({
      selector: 'root-comp',  //
      template: '<ng-content></ng-content>'
    })
    class RootComp {
    }

    @Component({
      selector: 'my-app',
      template: `
        <root-comp>
          <ng-container *ngFor="let item of items; last as last">
            <child-comp *ngIf="!last">{{ item }}|</child-comp>
          </ng-container>
        </root-comp>
      `
    })
    class MyApp {
      items: number[] = [1, 2, 3];
    }

    TestBed.configureTestingModule({declarations: [ChildComp, RootComp, MyApp]});
    const fixture = TestBed.createComponent(MyApp);
    fixture.detectChanges();

    // expecting # of elements to be (items.length - 1), since last element is filtered out by
    // *ngIf, this applies to all other assertions below
    expect(fixture.nativeElement).toHaveText('1|2|');

    fixture.componentInstance.items = [4, 5];
    fixture.detectChanges();
    expect(fixture.nativeElement).toHaveText('4|');

    fixture.componentInstance.items = [6, 7, 8, 9];
    fixture.detectChanges();
    expect(fixture.nativeElement).toHaveText('6|7|8|');
  });

  it('should project content if the change detector has been detached', () => {
    @Component({selector: 'my-comp', template: '<ng-content></ng-content>'})
    class MyComp {
      constructor(changeDetectorRef: ChangeDetectorRef) {
        changeDetectorRef.detach();
      }
    }

    @Component({
      selector: 'my-app',
      template: `
        <my-comp>
          <p>hello</p>
        </my-comp>
      `
    })
    class MyApp {
    }

    TestBed.configureTestingModule({declarations: [MyComp, MyApp]});
    const fixture = TestBed.createComponent(MyApp);
    fixture.detectChanges();

    expect(fixture.nativeElement).toHaveText('hello');
  });

  it('should support ngProjectAs with a various number of other bindings and attributes', () => {
    @Directive({selector: '[color],[margin]'})
    class ElDecorator {
      @Input() color?: string;
      @Input() margin?: number;
    }
    @Component({
      selector: 'card',
      template: `
        <ng-content select="[card-title]"></ng-content>
        ---
        <ng-content select="[card-subtitle]"></ng-content>
        ---
        <ng-content select="[card-content]"></ng-content>
        ---
        <ng-content select="[card-footer]"></ng-content>
      `
    })
    class Card {
    }

    @Component({
      selector: 'card-with-title',
      template: `
        <card>
         <h1 [color]="'red'" [margin]="10" ngProjectAs="[card-title]">Title</h1>
         <h2  xlink:href="google.com" ngProjectAs="[card-subtitle]">Subtitle</h2>
         <div style="font-color: blue;" ngProjectAs="[card-content]">content</div>
         <div [color]="'blue'" ngProjectAs="[card-footer]">footer</div>
        </card>
      `
    })
    class CardWithTitle {
    }

    TestBed.configureTestingModule({declarations: [Card, CardWithTitle, ElDecorator]});
    const fixture = TestBed.createComponent(CardWithTitle);
    fixture.detectChanges();

    // Compare the text output, because Ivy and ViewEngine produce slightly different HTML.
    expect(fixture.nativeElement.textContent)
        .toContain('Title --- Subtitle --- content --- footer');
  });

  it('should support ngProjectAs on elements (including <ng-content>)', () => {
    @Component({
      selector: 'card',
      template: `
        <ng-content select="[card-title]"></ng-content>
        ---
        <ng-content select="[card-content]"></ng-content>
      `
    })
    class Card {
    }

    @Component({
      selector: 'card-with-title',
      template: `
        <card>
         <h1 ngProjectAs="[card-title]">Title</h1>
         <ng-content ngProjectAs="[card-content]"></ng-content>
        </card>
      `
    })
    class CardWithTitle {
    }

    @Component({
      selector: 'app',
      template: `
        <card-with-title>content</card-with-title>
      `
    })
    class App {
    }

    TestBed.configureTestingModule({declarations: [Card, CardWithTitle, App]});
    const fixture = TestBed.createComponent(App);
    fixture.detectChanges();

    // Compare the text output, because Ivy and ViewEngine produce slightly different HTML.
    expect(fixture.nativeElement.textContent).toContain('Title --- content');
  });

  it('should not match multiple selectors in ngProjectAs', () => {
    @Component({
      selector: 'card',
      template: `
        <ng-content select="[card-title]"></ng-content>
        content
      `
    })
    class Card {
    }

    @Component({
      template: `
        <card>
         <h1 ngProjectAs="[non-existing-title-slot],[card-title]">Title</h1>
        </card>
      `
    })
    class App {
    }

    TestBed.configureTestingModule({declarations: [Card, App]});
    const fixture = TestBed.createComponent(App);
    fixture.detectChanges();

    // Compare the text output, because Ivy and ViewEngine produce slightly different HTML.
    expect(fixture.nativeElement.textContent).not.toContain('Title content');
  });

  it('should preserve ngProjectAs and other attributes on projected element', () => {
    @Component({
      selector: 'projector',
      template: `<ng-content select="projectMe"></ng-content>`,
    })
    class Projector {
    }

    @Component({
      template: `
        <projector>
          <div ngProjectAs="projectMe" title="some title"></div>
        </projector>
      `
    })
    class Root {
    }

    TestBed.configureTestingModule({
      declarations: [Root, Projector],
    });
    const fixture = TestBed.createComponent(Root);
    fixture.detectChanges();

    const projectedElement = fixture.debugElement.query(By.css('div'));
    const {ngProjectAs, title} = projectedElement.attributes;
    expect(ngProjectAs).toBe('projectMe');
    expect(title).toBe('some title');
  });

  describe('on inline templates (e.g.  *ngIf)', () => {
    it('should work when matching the element name', () => {
      let divDirectives = 0;
      @Component({selector: 'selector-proj', template: '<ng-content select="div"></ng-content>'})
      class SelectedNgContentComp {
      }

      @Directive({selector: 'div'})
      class DivDirective {
        constructor() {
          divDirectives++;
        }
      }

      @Component({
        selector: 'main-selector',
        template: '<selector-proj><div x="true" *ngIf="true">Hello world!</div></selector-proj>'
      })
      class SelectorMainComp {
      }

      TestBed.configureTestingModule(
          {declarations: [DivDirective, SelectedNgContentComp, SelectorMainComp]});
      const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);

      fixture.detectChanges();
      expect(fixture.nativeElement).toHaveText('Hello world!');
      expect(divDirectives).toEqual(1);
    });

    it('should work when matching attributes', () => {
      let xDirectives = 0;
      @Component({selector: 'selector-proj', template: '<ng-content select="[x]"></ng-content>'})
      class SelectedNgContentComp {
      }

      @Directive({selector: '[x]'})
      class XDirective {
        constructor() {
          xDirectives++;
        }
      }

      @Component({
        selector: 'main-selector',
        template: '<selector-proj><div x="true" *ngIf="true">Hello world!</div></selector-proj>'
      })
      class SelectorMainComp {
      }

      TestBed.configureTestingModule(
          {declarations: [XDirective, SelectedNgContentComp, SelectorMainComp]});
      const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);

      fixture.detectChanges();
      expect(fixture.nativeElement).toHaveText('Hello world!');
      expect(xDirectives).toEqual(1);
    });

    it('should work when matching classes', () => {
      let xDirectives = 0;
      @Component({selector: 'selector-proj', template: '<ng-content select=".x"></ng-content>'})
      class SelectedNgContentComp {
      }

      @Directive({selector: '.x'})
      class XDirective {
        constructor() {
          xDirectives++;
        }
      }

      @Component({
        selector: 'main-selector',
        template: '<selector-proj><div class="x" *ngIf="true">Hello world!</div></selector-proj>'
      })
      class SelectorMainComp {
      }

      TestBed.configureTestingModule(
          {declarations: [XDirective, SelectedNgContentComp, SelectorMainComp]});
      const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);

      fixture.detectChanges();
      expect(fixture.nativeElement).toHaveText('Hello world!');
      expect(xDirectives).toEqual(1);
    });

    it('should ignore synthesized attributes (e.g. ngTrackBy)', () => {
      @Component(
          {selector: 'selector-proj', template: '<ng-content select="[ngTrackBy]"></ng-content>'})
      class SelectedNgContentComp {
      }

      @Component({
        selector: 'main-selector',
        template:
            'inline(<selector-proj><div *ngFor="let item of items trackBy getItemId">{{item.name}}</div></selector-proj>)' +
            'ng-template(<selector-proj><ng-template ngFor [ngForOf]="items" let-item ngTrackBy="getItemId"><div>{{item.name}}</div></ng-template></selector-proj>)'
      })
      class SelectorMainComp {
        items = [
          {id: 1, name: 'one'},
          {id: 2, name: 'two'},
          {id: 3, name: 'three'},
        ];
        getItemId(item: {id: number}) {
          return item.id;
        }
      }

      TestBed.configureTestingModule({declarations: [SelectedNgContentComp, SelectorMainComp]});
      const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);

      fixture.detectChanges();
      expect(fixture.nativeElement).toHaveText('inline()ng-template(onetwothree)');
    });

    it('should project template content with `ngProjectAs` defined', () => {
      @Component({
        selector: 'projector-app',
        template: `
          Projected
          <ng-content select="foo"></ng-content>
          <ng-content select="[foo]"></ng-content>
          <ng-content select=".foo"></ng-content>
        `,
      })
      class ProjectorApp {
      }

      @Component({
        selector: 'root-comp',
        template: `
          <projector-app>
            <div *ngIf="show" ngProjectAs="foo">as element</div>
            <div *ngIf="show" ngProjectAs="[foo]">as attribute</div>
            <div *ngIf="show" ngProjectAs=".foo">as class</div>
          </projector-app>
        `,
      })
      class RootComp {
        show = true;
      }

      TestBed.configureTestingModule({
        declarations: [ProjectorApp, RootComp],
      });
      const fixture = TestBed.createComponent(RootComp);
      fixture.detectChanges();

      let content = fixture.nativeElement.textContent;
      expect(content).toContain('as element');
      expect(content).toContain('as attribute');
      expect(content).toContain('as class');

      fixture.componentInstance.show = false;
      fixture.detectChanges();

      content = fixture.nativeElement.textContent;
      expect(content).not.toContain('as element');
      expect(content).not.toContain('as attribute');
      expect(content).not.toContain('as class');
    });

    describe('on containers', () => {
      it('should work when matching attributes', () => {
        let xDirectives = 0;
        @Component({selector: 'selector-proj', template: '<ng-content select="[x]"></ng-content>'})
        class SelectedNgContentComp {
        }

        @Directive({selector: '[x]'})
        class XDirective {
          constructor() {
            xDirectives++;
          }
        }

        @Component({
          selector: 'main-selector',
          template:
              '<selector-proj><ng-container x="true">Hello world!</ng-container></selector-proj>'
        })
        class SelectorMainComp {
        }

        TestBed.configureTestingModule(
            {declarations: [XDirective, SelectedNgContentComp, SelectorMainComp]});
        const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);

        fixture.detectChanges();
        expect(fixture.nativeElement).toHaveText('Hello world!');
        expect(xDirectives).toEqual(1);
      });

      it('should work when matching classes', () => {
        let xDirectives = 0;
        @Component({selector: 'selector-proj', template: '<ng-content select=".x"></ng-content>'})
        class SelectedNgContentComp {
        }

        @Directive({selector: '.x'})
        class XDirective {
          constructor() {
            xDirectives++;
          }
        }

        @Component({
          selector: 'main-selector',
          template:
              '<selector-proj><ng-container class="x">Hello world!</ng-container></selector-proj>'
        })
        class SelectorMainComp {
        }

        TestBed.configureTestingModule(
            {declarations: [XDirective, SelectedNgContentComp, SelectorMainComp]});
        const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);

        fixture.detectChanges();
        expect(fixture.nativeElement).toHaveText('Hello world!');
        expect(xDirectives).toEqual(1);
      });
    });
  });
});