range

Creates an Observable that emits a sequence of numbers within a specified range

range

Creates an Observable that emits a sequence of numbers within a specified range.

Import

import { range } from 'rxjs';

Type Signature

function range(start: number, count?: number): Observable<number>;

Parameters

start · number · required

The value of the first integer in the sequence. If count is not provided, this becomes the count and start defaults to 0.

count · number

The number of sequential integers to generate.

Returns

Observable · Observable<number>

An Observable that emits a finite range of sequential integers.

Description

range emits a sequence of sequential integers synchronously.

Examples

Basic Range

import { range } from 'rxjs';

range(1, 3).subscribe({
  next: x => console.log(x),
  complete: () => console.log('Complete!')
});

// Output:
// 1
// 2
// 3
// Complete!

Count Only

import { range } from 'rxjs';

// When only one argument, it's the count (starts from 0)
range(5).subscribe(x => console.log(x));

// Output:
// 0
// 1
// 2
// 3
// 4

Common Use Cases

Generate Test Data

import { range } from 'rxjs';
import { map } from 'rxjs/operators';

range(1, 100).pipe(
  map(i => ({ id: i, name: `User ${i}` }))
).subscribe(user => console.log(user));

Related Operators

• of - Emit specific values
• generate - Generate with custom logic
• interval - Emit periodically

See Also

• Official RxJS Documentation