This simple utility uses Promises to implement a bucket-type rate limiter to be respectful of api rate limits. After using up the tokens in the bucket, it queues any additional calls and resolves them when the bucket is refilled.
Use it either with the Promise api, or – more conveniently – with await (only works in asyncfunctions, not on the top-level).
const rateLimit = require('throttle-bucket')({ bucketSize: 3, bucketRefreshDelay: 10000 })
rateLimit().then(() => { console.log('Request 1') })
// executed immediately
rateLimit().then(() => { console.log('Request 2') })
// executed immediately
rateLimit().then(() => { console.log('Request 3') })
// executed immediately, starts countdown for refilling the bucket after 10 seconds
rateLimit().then(() => { console.log('Request 4') })
// executed when the bucket is refilled
rateLimit(3).then(() => { console.log('Request 5') })
// you can set a higher numbers of tokens if you plan to make multiple api calls. This call will set a timeout for refilling the bucket and will execute only after the bucket is refilled.
rateLimit().then(() => { console.log('Request 6') })
// This call does not jump ahead of Request 5 in the queue due to the naive implementation. It will execute after the bucket is refilled again.const rateLimit = require('throttle-bucket')({ bucketSize: 3, bucketRefreshDelay: 10000 })
async function apiRequests() {
await rateLimit() // before each api call, *await* a rateLimit call.
console.log('Request 1') // executed immediately
await rateLimit(2) // set a higher number of tokens if you plan to make multiple api calls (or use a more costly api method). As this uses the last two tokens in the bucket, a countdown for the refilling is set.
console.log('Request 2') // executed immediately,
console.log('Request 3') // executed immediately,
await rateLimit()
console.log('Request 4') // executed after the bucket is refilled
}MIT License
Copyright (c) 2020 Simon Ruf
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