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debounce

signature: debounce(durationSelector: function): Observable

Discard emitted values that take less than the specified time, based on selector function, between output.

💡 Though not as widely used as debounceTime, debounce is important when the debounce rate is variable!

Examples

Example 1: Debounce on timer
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// RxJS v6+
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import { of, timer } from 'rxjs';
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import { debounce } from 'rxjs/operators';
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//emit four strings
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const example = of('WAIT', 'ONE', 'SECOND', 'Last will display');
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/*
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Only emit values after a second has passed between the last emission,
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throw away all other values
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*/
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const debouncedExample = example.pipe(debounce(() => timer(1000)));
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/*
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In this example, all values but the last will be omitted
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output: 'Last will display'
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*/
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const subscribe = debouncedExample.subscribe(val => console.log(val));
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Example 2: Debounce at increasing interval
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// RxJS v6+
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import { interval, timer } from 'rxjs';
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import { debounce } from 'rxjs/operators';
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//emit value every 1 second, ex. 0...1...2
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const interval$ = interval(1000);
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//raise the debounce time by 200ms each second
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const debouncedInterval = interval$.pipe(debounce(val => timer(val * 200)));
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/*
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After 5 seconds, debounce time will be greater than interval time,
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all future values will be thrown away
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output: 0...1...2...3...4......(debounce time over 1s, no values emitted)
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*/
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const subscribe = debouncedInterval.subscribe(val =>
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console.log(`Example Two: ${val}`)
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);
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Additional Resources