Control Flow in Components - @for

Often when building web applications, you need to repeat some code a specific number of times - for example, given an array of names, you may want to display each name in a <p> tag.

Note: Learn more about control flow in the essentials guide.

In this activity, you'll learn how to use @for to repeat elements in a template.

The syntax that enables repeating elements in a template is @for.

Here's an example of how to use the @for syntax in a component:

@Component({  ...  template: `    @for (os of operatingSystems; track os.id) {      {{ os.name }}    }  `,})export class App {  operatingSystems = [{id: 'win', name: 'Windows'}, {id: 'osx', name: 'MacOS'}, {id: 'linux', name: 'Linux'}];}

Two things to take note of:

• There is an @ prefix for the for because it is a special syntax called Angular template syntax
• For applications using v16 and older please refer to the Angular documentation for NgFor

1. Add the users property

   In the App class, add a property called users that contains users and their names.

   [{id: 0, name: 'Sarah'}, {id: 1, name: 'Amy'}, {id: 2, name: 'Rachel'}, {id: 3, name: 'Jessica'}, {id: 4, name: 'Poornima'}]

2. Update the template

   Update the template to display each user name in a p element using the @for template syntax.

   @for (user of users; track user.id) {  <p>{{ user.name }}</p>}

   NOTE: the use of track is required, you may use the id or some other unique identifier.

This type of functionality is called control flow. Next, you'll learn to customize and communicate with components - by the way, you're doing a great job so far.