https://github.com/sindresorhus/p-map-series

Map over promises serially
https://github.com/sindresorhus/p-map-series

Last synced: about 2 months ago
JSON representation

Map over promises serially

• Host: GitHub
• URL: https://github.com/sindresorhus/p-map-series
• Owner: sindresorhus
• License: mit
• Created: 2016-10-21T04:26:03.000Z (over 7 years ago)
• Default Branch: main
• Last Pushed: 2021-04-09T06:29:45.000Z (about 3 years ago)
• Last Synced: 2024-03-22T08:58:16.287Z (3 months ago)
• Language: JavaScript
• Size: 12.7 KB
• Stars: 46
• Watchers: 8
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • Funding: .github/funding.yml
  • License: license
  • Security: .github/security.md

Lists

• awesome-promises - p-map-series - Map over promises serially (Convenience Utilities / sindresorhus's many Promise utilities ([see notes](https://github.com/sindresorhus/promise-fun)))
• promise-fun - p-map-series

README

        
# p-map-series

> Map over promises serially

Useful as a side-effect mapper. Use [`p-map`](https://github.com/sindresorhus/p-map) if you don't need side-effects, as it's concurrent.

## Install

```

$ npm install p-map-series

```

## Usage

```js

import pMapSeries from 'p-map-series';

const keywords = [

	getTopKeyword() //=> Promise

	'rainbow',

	'pony'

];

let scores = [];

const mapper = async keyword => {

	const score = await fetchScore(keyword);

	scores.push(score);

	return {keyword, score};

});

console.log(await pMapSeries(keywords, mapper));

/*

[

	{

		keyword: 'unicorn',

		score: 99

	},

	{

		keyword: 'rainbow',

		score: 70

	},

	{

		keyword: 'pony',

		score: 79

	}

]

*/

```

## API

### pMapSeries(input, mapper)

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 `mapper` created promises fulfillment values.

#### input

Type: `Iterable`

Mapped over serially in the `mapper` function.

#### mapper(element, index)

Type: `Function`

Expected to return a value. If it's a `Promise`, it's awaited before continuing with the next iteration.

## Related

- [p-each-series](https://github.com/sindresorhus/p-each-series) - Iterate over promises serially

- [p-reduce](https://github.com/sindresorhus/p-reduce) - Reduce a list of values using promises into a promise for a value

- [p-map](https://github.com/sindresorhus/p-map) - Map over promises concurrently

- [More…](https://github.com/sindresorhus/promise-fun)

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