takewhile.md

takeWhile

signature: takeWhile(predicate: function(value, index): boolean): Observable

Emit values until provided expression is false.

Examples

Example 1: Take values under limit

( jsBin | jsFiddle )

//emit 1,2,3,4,5
const source = Rx.Observable.of(1,2,3,4,5);
//allow values until value from source is greater than 4, then complete
const example = source.takeWhile(val => val <= 4);
//output: 1,2,3,4
const subscribe = example.subscribe(val => console.log(val));

Related Recipes

• Smart Counter

Additional Resources

• takeWhile 📰 - Official docs
• Completing a stream with takeWhile 📹 💵 - John Linquist

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📁 Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/operator/takeWhile.ts