Transclusion using ng-content

Understanding Transclusion
Transclusion means the inclusion of the content of one document in another document.

Content Projection in Angular with ng-content
Let’s say you have a home component with a decorator that goes a bit like this:

@Component({

    selector: 'home',

    template: `

      <h1>Heroic Title</h1>

      <p>Something good...</p>

    `

  })

And let’s say you want to be able to do something like this when including the component:

<home>

  <p>Something else</p>

</home>

Then what you would do is use <ng-content></ng-content> like this in your component template:

@Component({

    selector: 'home',

    template: `

      <h1>Heroic Title</h1>

      <p>Something good...</p>

      <ng-content></ng-content>

    `

  })

The result will then be the following:

<h1>Heroic Title</h1>

<p>Something good...</p>

<p>Something else</p>

And with this, you could also place components inside your wrapper component. Here’s how you would, for example, project the myNav component inside the home component:

<home>

  <myNav></myNav>

</home>

You can also use select on ng-content to define what should be included. In this example, only div elements would be included:

@Component({

    selector: 'home',

    template: `

      <h1>Heroic Title</h1>

      <p>Something good...</p>

      <ng-content select="div">

      </ng-content>

    `

  })

And you can use the [attr] syntax to select only elements that have a specific attribute. In the following example, only something like <p intro>…</p> would be included:

@Component({

    selector: 'home',

    template: `

      <h1>Heroic Title</h1>

      <p>Something good...</p>

      <ng-content select="[intro]">

      </ng-content>

    `

  })

Reference: https://alligator.io/, https://medium.com/, https://codecraft.tv/