dylanb / p-throttle

Throttle promise-returning & async functions

p-throttle

Throttle promise-returning & async functions

It also works with normal functions.

Useful for rate limiting calls to an external API, for example.

Install

$ npm install --save p-throttle

Usage

Here, the trottled function is only called twice a second:

const pThrottle = require('p-throttle');

const now = Date.now();

const throttled = pThrottle(i => {
	const secDiff = ((Date.now() - now) / 1000).toFixed();
	return Promise.resolve(`${i}: ${secDiff}s`);
}, 2, 1000);

for (let i = 1; i <= 6; i++) {
	throttled(i).then(console.log);
}
//=> 1: 0s
//=> 2: 0s
//=> 3: 1s
//=> 4: 1s
//=> 5: 2s
//=> 6: 2s

API

pThrottle(fn, limit, interval)

Returns a throttled version of fn.

fn

Type: Function

Promise-returning/async function or a normal function.

limit

Type: number

Maximum number of calls within an interval.

interval

Type: number

Timespan for limit.

Related

• p-debounce - Debounce promise-returning & async functions
• p-limit - Run multiple promise-returning & async functions with limited concurrency
• p-memoize - Memoize promise-returning & async functions
• More…

License

MIT © Sindre Sorhus