sample

signature: sample(sampler: Observable): Observable

Sample from source when provided observable emits.

Examples

Example 1: Sample source every 2 seconds

( jsBin | jsFiddle )

//emit value every 1s
const source = Rx.Observable.interval(1000);
//sample last emitted value from source every 2s 
const example = source.sample(Rx.Observable.interval(2000));
//output: 2..4..6..8..
const subscribe = example.subscribe(val => console.log(val));
Example 2: Sample source when interval emits

( jsBin | jsFiddle )

const source = Rx.Observable.zip(
  //emit 'Joe', 'Frank' and 'Bob' in sequence
  Rx.Observable.from(['Joe', 'Frank', 'Bob']),
  //emit value every 2s
  Rx.Observable.interval(2000)
);
//sample last emitted value from source every 2.5s
const example = source.sample(Rx.Observable.interval(2500));
//output: ["Joe", 0]...["Frank", 1]...........
const subscribe = example.subscribe(val => console.log(val));

Additional Resources


:file_folder: Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/operator/sample.ts

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