distinct

signature: distinct(keySelector?, flushes?): Observable

Emits items emitted that are distinct based on any previously emitted item.

Examples

Example 1: distinct without selector

( StackBlitz )

// RxJS v6+
import { of } from 'rxjs';
import { distinct } from 'rxjs/operators';

of(1, 2, 3, 4, 5, 1, 2, 3, 4, 5)
  .pipe(distinct())
  // OUTPUT: 1,2,3,4,5
  .subscribe(console.log);

Example 2: distinct with key selector

( StackBlitz )

// RxJS v6+
import { from } from 'rxjs';
import { distinct } from 'rxjs/operators';

const obj1 = { id: 3, name: 'name 1' };
const obj2 = { id: 4, name: 'name 2' };
const obj3 = { id: 3, name: 'name 3' };
const vals = [obj1, obj2, obj3];

from(vals)
  .pipe(distinct(e => e.id))
  .subscribe(console.log);

/*
OUTPUT:
{id: 3, name: "name 1"}
{id: 4, name: "name 2"}
 */

Additional Resources

• distinct 📰 - Official docs

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📁 Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/distinct.ts