throttlify

A function that returns a throttled variant of a Promise-returning function.

Installation

yarn add throttlify

OR

npm i throttlify

Usage

Prerequisites

• node@>=8.3.0

API

throttlify(asyncFn, [opts], [ctx])

• asyncFn {Function} asynchronous function (required)
• [opts] {Object} throttle options
  • [concurrent] {Number} maximum number of concurrent requests
  • [duration=60000] {Number} throttle duration in milliseconds
  • [max=60] {Number} maximum number of requests per duration
• [ctx] {Object} this parameter for the asyncFn function
• returns {Function} throttled asynchronous function

Code Example

'use strict';

const throttlify = require('throttlify');
const fetch = require('node-fetch');

const throttledFetch = throttlify(fetch, { duration: 60000, max: 45 });
const url = 'https://jsonplaceholder.typicode.com/posts';

// create 45 requests
Array.from(new Array(45)).forEach((v, i) => throttledFetch(`${url}/${i + 1}`));

// 46th request executes 60 seconds after first request
throttledFetch(url)
  .then(res => res.json())
  .then(body => console.log(body))
  .catch(err => console.error(err));

Development

Merge requests should be submitted to https://gitlab.com/wondermonger/throttlify.

Installation

yarn

Linting

yarn lint

Testing

# all tests
yarn test

# integration tests
yarn test:integration

# unit tests
yarn test:unit

# coverage tests
yarn test:coverage

The integration tests create an ephemeral Node.js server that requires a connection to a Redis instance. The default configuration can be overridden by setting environment variables prior to executing yarn test or yarn test:integration.

# default values
NODE_HOST="localhost"
NODE_PORT="3000"
REDIS_DB="0"
REDIS_HOST="localhost"
REDIS_PASSWORD=""
REDIS_PORT="6379"

License

The MIT License (MIT)

Copyright (c) 2018 Michael J. Bondra [email protected]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.