Code snippet: a simple rate limiter

#typescript #javascript

This code snippet is different from my previous one: A performant async queue. Even if it works quite the same way.

The big difference is that it runs functions after some wait time, instead of waiting some time after functions have finished to run.

There's also an NPM package: dumb-limiter.

	/*
	How to use:

	import limiter from './limiter'
	const limit = limiter(<wait_time_in_ms>)
	limit(() => console.log('foo'))
	limit(async () => console.log('bar'))
	*/
	export default (interval : number) => {
	if (interval <= 0) {
	throw new Error("'interval' must be a positive integer")
	}

	const queue : Array<() => (void \| Promise<void>)> = []

	const unqueue = () => {
	const callback = queue.shift()
	if (callback) {
	callback()
	}
	}

	setInterval(unqueue, interval)

	return (callback : () => (void \| Promise<void>)) => {
	queue.push(callback)
	}
	}