Requestq NPM | npm.io

requestq

A tiny, intelligent queue for ajax requests in the browser:

Prioritize requests, even cancelling long-running low-priority requests when high-priority requests come in.
Throttle requests, executing only a set number at a time
Retry requests
Only 2KB (minified and gzipped)

Installation

npm install requestq --save

If you need to support most browsers, you will also need a Promise polyfill if you do not already have one:

npm install promise-polyfill --save-exact

Usage

import {RequestQueue} from 'requestq';

const requests = new RequestQueue()
requests.get('https://example.com/terms.txt').then((response) => {
  console.log('Got terms: ', response)  
}).catch(() => {
  console.error('Request failed')
})

Advanced Usage

import {RequestQueue, RequestPriority} from 'requestq';

const requests = new RequestQueue({
    retries: 3,
    concurrency: 5
})

let terms = requests.get('https://example.com/terms.txt), {
  priority: RequestPriority.LOW
}).then((response) => {
  console.log('Got terms: ' + response)  
}).catch(() => {
  console.error('Request failed after 3 retries')
})

let names = requests.get('https://example.com/names.json', {
    priority: RequestPriority.HIGHEST,
    responseType: 'json'
}).then((response) => {
  // Use the response object
}).catch(() => {
  console.error('Request failed after 3 retries')
})
await Promise.all([terms, names])

Documentation

new RequestQueue({options})

Makes a new RequestQueue. Options:

retries: number of times a GET request will be retried on errors. (Default: 3)
- Only GET requests are retried, as retrying POST can create duplicate objects or unwanted effects.
concurrency: number of concurrent requests the queue can have in-flight (Default: 6)

RequestQueue.request(method, url, {options})

Puts request in the queue. Returns a promise that resolves when the request is done, or rejects if it fails.

method: the HTTP method for the request, e.g. "GET"
url: The URL for the request
options:
- priority: Defines the order in which requests get sent. One of the following:
  - RequestQueue.LOW
  - RequestQueue.MEDIUM (default)
  - RequestQueue.HIGH
  - RequestQueue.HIGHEST
    HIGHEST is special: It actually aborts HIGH, MEDIUM or LOW requests to be tried again, if there are too many requests in flight)
- body: The request body if applicable. Either a string or an object (automatically JSON.stringified)
- maxRetries: The maximum number of retries that this request will use, overrides the main RequestQueue retries.
- responseType: One of the following:
  - null (default, uses browser behavior)
  - json: Parses the response as JSON and returns an object. Sets Accept: application/json as a request header.
  - text: Returns the response as text
  - blob: Returns a Blob
  - arraybuffer: Returns an ArrayBuffer
  - image: Returns an Image
- headers: Object of additional headers to set
- auth: contents of the 'Authorization' header if supplied
- withCredentials: Enable or disable sending credentials with cross-site XHR requests (default false)