@madfish-solutions/p-throttle-ts

Throttle promise-returning & async functions

It also works with normal functions.

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

This module is p-throttle rewritten to Typescript to make its integration into projects easier.

Install

npm install @madfish-solutions/p-throttle-ts

Usage

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

import pThrottle from '@madfish-solutions/p-throttle-ts';

const now = Date.now();

const throttle = pThrottle({
	limit: 2,
	interval: 1000
});

const throttled = throttle(async index => {
	const secDiff = ((Date.now() - now) / 1000).toFixed();
	return `${index}: ${secDiff}s`;
});

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

API

pThrottle(options)

Returns a throttle function.

options

Type: object

Both the limit and interval options must be specified.

limit

Type: number

The maximum number of calls within an interval.

interval

Type: number

The timespan for limit in milliseconds.

strict

Type: boolean
Default: false

Use a strict, more resource intensive, throttling algorithm. The default algorithm uses a windowed approach that will work correctly in most cases, limiting the total number of calls at the specified limit per interval window. The strict algorithm throttles each call individually, ensuring the limit is not exceeded for any interval.

throttle(function_)

Returns a throttled version of function_.

function_

Type: Function

A promise-returning/async function or a normal function.

throttledFn.abort()

Abort pending executions. All unresolved promises are rejected with a pThrottle.AbortError error.

throttledFn.isEnabled

Type: boolean
Default: true

Whether future function calls should be throttled and count towards throttling thresholds.

throttledFn.queueSize

Type: number

The number of queued items waiting to be executed.

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…