range

Emits consecutive integers over a given range.

Signature

range(start: number, count?: number): Observable

Marble diagram

range(10, 3):  (10 11 12 |)

What it does

Creates a stream of count numbers starting from start. It all happens synchronously and the stream completes. If count is omitted it defaults to Number.POSITIVE_INFINITY (don't run that in production without take).

When to use

When you need a predictable sequence of indices: iterating, batching by N, tests with deterministic values. Often combined with map to generate richer values from the index.

See also

of, generate, interval