Requests Throttler

Node.js module for making throttled queue of functions/requests. This can be useful when you are working with an external API, where the number of requests per second is important.

Installing

npm i requests-throttler

Usage

Fisrt things first. Init Throttler

const Throttler = require('requests-throttler');

Create new instance of Throttler and provide 2 parameters.

• ms - is the deley between each execution
• limit - is how many executions can be active in the same time. Another words - parallel execution limit.

const queue = new Throttler(ms, limit);

And wrap you target request with Throttler

queue.add(() => {
 // your code here
}

It is important to clear your queue as requests complete.

queue.checkout();

this method will clear queue for 1 position.

Examples

const fetch = require('node-fetch');
const Throttler = require('requests-throttler'); // init throttler

let ms = 500; // 500 ms between requests
let limit = 2; // 2 request can be proceeded at the same time
const queue = new Throttler(ms, limit); // make a new instanse of the throttler
for (var i = 0; i < 100; i++) {
  queue.add(() => {
    //make a network request
    fetch('https://api.github.com/search/users?q=buzzik')
      .then((res) => res.json())
      .then((json) => {
        console.log(json);
        // freeing the queue from ready requests
        queue.checkout();
      });
  });
}

The requests will starting to execute right after first request will be added.