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API > @angular/common

KeyValuePipe

Transforms Object or Map into an array of key value pairs.

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{{ input_expression | keyvalue [ : compareFn ] }}
      
      {{ input_expression | keyvalue [ : compareFn ] }}

NgModule

Input value

input null | { [key: string]: V; [key: number]: V; } | Map

Parameters

compareFn (a: KeyValue, b: KeyValue) => number

Optional. Default is defaultComparator.

Description

The output array will be ordered by keys. By default the comparator will be by Unicode point value. You can optionally pass a compareFn if your keys are complex types.

Usage notes

Examples

This examples show how an Object or a Map and be iterated by ngFor with the use of this keyvalue pipe.

@Component({ selector: 'keyvalue-pipe', template: `<span> <p>Object</p> <div *ngFor="let item of object | keyvalue"> {{item.key}}:{{item.value}} </div> <p>Map</p> <div *ngFor="let item of map | keyvalue"> {{item.key}}:{{item.value}} </div> </span>` }) export class KeyValuePipeComponent { object: {[key: number]: string} = {2: 'foo', 1: 'bar'}; map = new Map([[2, 'foo'], [1, 'bar']]); } 
      
      
  1. @Component({
  2.   selector: 'keyvalue-pipe',
  3.   template: `<span>
  4.     <p>Object</p>
  5.     <div *ngFor="let item of object | keyvalue">
  6.       {{item.key}}:{{item.value}}
  7.     </div>
  8.     <p>Map</p>
  9.     <div *ngFor="let item of map | keyvalue">
  10.       {{item.key}}:{{item.value}}
  11.     </div>
  12.   </span>`
  13. })
  14. export class KeyValuePipeComponent {
  15.   object: {[key: number]: string} = {2: 'foo', 1: 'bar'};
  16.   map = new Map([[2, 'foo'], [1, 'bar']]);
  17. }