sample
Example 1: Sample source every 2 seconds
// RxJS v6+
import { interval } from 'rxjs';
import { sample } from 'rxjs/operators';
//emit value every 1s
const source = interval(1000);
//sample last emitted value from source every 2s
const example = source.pipe(sample(interval(2000)));
//output: 2..4..6..8..
const subscribe = example.subscribe(val => console.log(val));
Example 2: Sample source when interval emits
// RxJS v6+
import { interval, zip, from } from 'rxjs';
import { sample } from 'rxjs/operators';
const source = zip(
//emit 'Joe', 'Frank' and 'Bob' in sequence
from(['Joe', 'Frank', 'Bob']),
//emit value every 2s
interval(2000)
);
//sample last emitted value from source every 2.5s
const example = source.pipe(sample(interval(2500)));
//output: ["Joe", 0]...["Frank", 1]...........
const subscribe = example.subscribe(val => console.log(val));
Example 3: Distinguish between drag and click
// RxJS v6+
import { fromEvent, merge } from 'rxjs';
import { sample, mapTo } from 'rxjs/operators';
const listener = merge(
fromEvent(document, 'mousedown').pipe(mapTo(false)),
fromEvent(document, 'mousemove').pipe(mapTo(true))
)
.pipe(sample(fromEvent(document, 'mouseup')))
.subscribe(isDragging => {
console.log('Were you dragging?', isDragging);
});
Last modified 3yr ago