BACK
ReferenceelementAt
RUEN
Reference · 59

elementAt

elementAt

rxjs.dev

Takes the value at an index and completes the stream.

Signature

elementAt(index: number, defaultValue?: D): OperatorFunction

What it does

Counts values from zero. When it reaches the target index, it emits the value and ends the subscription.

When to use

Tests, protocols with a fixed message number, picking a specific step from a finite sequence.

Gotcha

If the index is never reached and no defaultValue is given, the stream fails with ArgumentOutOfRangeError.

See also

first, last, skip

script.ts // TypeScript
CONSOLE · Console output
Hit Run to see the result...