Render content between the component tags

When a component is rendered, content inside it is ignored, for example:

import { Component } from '@angular/core';
@Component({
  selector: 'app-root',
  template: '<div>{{title}}</div>',
})
export class AppComponent {
  title = 'app works!';
}

Using it like:

<app-root>Ignored content</app-root>

Renders:

<div>app works!</div>

But looking at PrimeNg dialog, they use components like this:

<p-dialog [(visible)]="display">
    <p-header>
        Header content here
    </p-header>
    Content
    <p-footer>
        Footer content here
   </p-footer>
</p-dialog>

As Header content here, Content and Footer content here are inside the component, why are not they getting ignored and how can I achieve this?

Add <ng-content></ng-content> to the component's template where the content should be projected:

@Component({
  selector: 'app-demo',
  template: '<div>{{title}}</div>
             <br>
             <ng-content></ng-content>',
})
export class DemoComponent {
  title = 'Works!';
}

Content to be projected:

<app-demo>This is projected content!</app-demo>

The output will be:

Works!
This is projected content!

Here is a great article about Angular Content Projection (Angular 1 Transclusion): Transclusion in Angular 2 with ng-content