# p-map [![Build Status](https://travis-ci.org/sindresorhus/p-map.svg?branch=master)](https://travis-ci.org/sindresorhus/p-map) > Map over promises concurrently Useful when you need to run promise-returning & async functions multiple times with different inputs concurrently. ## Install ``` $ npm install p-map ``` ## Usage ```js const pMap = require('p-map'); const got = require('got'); const sites = [ getWebsiteFromUsername('sindresorhus'), //=> Promise 'ava.li', 'todomvc.com', 'github.com' ]; (async () => { const mapper = async site => { const {requestUrl} = await got.head(site); return requestUrl; }; const result = await pMap(sites, mapper, {concurrency: 2}); console.log(result); //=> ['http://sindresorhus.com/', 'http://ava.li/', 'http://todomvc.com/', 'http://github.com/'] })(); ``` ## API ### pMap(input, mapper, [options]) Returns a `Promise` that is fulfilled when all promises in `input` and ones returned from `mapper` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values returned from `mapper` in `input` order. #### input Type: `Iterable` Iterated over concurrently in the `mapper` function. #### mapper(element, index) Type: `Function` Expected to return a `Promise` or value. #### options Type: `Object` ##### concurrency Type: `number`
Default: `Infinity`
Minimum: `1` Number of concurrently pending promises returned by `mapper`. ## Related - [p-all](https://github.com/sindresorhus/p-all) - Run promise-returning & async functions concurrently with optional limited concurrency - [p-filter](https://github.com/sindresorhus/p-filter) - Filter promises concurrently - [p-times](https://github.com/sindresorhus/p-times) - Run promise-returning & async functions a specific number of times concurrently - [p-props](https://github.com/sindresorhus/p-props) - Like `Promise.all()` but for `Map` and `Object` - [p-map-series](https://github.com/sindresorhus/p-map-series) - Map over promises serially - [p-queue](https://github.com/sindresorhus/p-queue) - Promise queue with concurrency control - [More…](https://github.com/sindresorhus/promise-fun) ## License MIT © [Sindre Sorhus](https://sindresorhus.com)