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# 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<Promise|any>`
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`<br>
Default: `Infinity`<br>
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)

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