How to ask for the size of array in Angular2 using interpolation?

Question

How can I ask about the size of an array in angular 2 when I am using it in a component, for example:

users : User[];

with

export class User {
  id : number;
  firstName : String;
  lastName  : String;
  userName  : String
}

and

  <tbody>
    <tr *ngFor="let user of users">
      <th scope="row">{{ user.id }}</th>
      <td>{{ user.firstName }}</td>
      <td>{{ user.lastName }}</td>
      <td>{{ user.userName }}</td>
    </tr>
  </tbody>

what should be the way to ask for the size on array inside a *ngIf expression using interpolation to detect it the size is different to empty?

Antoine Clavijo · Accepted Answer · 2017-03-02 15:55:22Z

2

<tbody *ngIf="users.length">
    <tr *ngFor="let user of users">
      <th scope="row">{{ user.id }}</th>
      <td>{{ user.firstName }}</td>
      <td>{{ user.lastName }}</td>
      <td>{{ user.userName }}</td>
    </tr>
</tbody>

answered Mar 2, 2017 at 15:55

Antoine Clavijo

1,3052 gold badges11 silver badges19 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Pablo Ezequiel Inchausti Over a year ago

thanks! it worked ok, one more question: how do you do make evaluations like "length equal to 3" o "length is different to 2"?

Antoine Clavijo Over a year ago

the *ngIf wait a result of a conditionnal comparaison. So you can reuse the same syntax to evaluate other state like users.length == 3 or users.length != 2 and display/hidden other html block.

Collectives™ on Stack Overflow

How to ask for the size of array in Angular2 using interpolation?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related