https://github.com/sindresorhus/p-waterfall

Run promise-returning & async functions in series, each passing its result to the next
https://github.com/sindresorhus/p-waterfall

Last synced: about 1 month ago
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Run promise-returning & async functions in series, each passing its result to the next

• Host: GitHub
• URL: https://github.com/sindresorhus/p-waterfall
• Owner: sindresorhus
• License: mit
• Created: 2016-11-22T07:34:00.000Z (almost 8 years ago)
• Default Branch: main
• Last Pushed: 2021-04-09T06:43:12.000Z (over 3 years ago)
• Last Synced: 2024-05-22T18:05:48.807Z (6 months ago)
• Language: TypeScript
• Size: 16.6 KB
• Stars: 73
• Watchers: 6
• Forks: 4
• Open Issues: 1
• Metadata Files:
  • Readme: readme.md
  • Funding: .github/funding.yml
  • License: license
  • Security: .github/security.md

Awesome Lists containing this project

• promise-fun - p-waterfall - returning & async functions in series, each passing its result to the next (Packages)

README

        
# p-waterfall

> Run promise-returning & async functions in series, each passing its result to the next

## Install

```

$ npm install p-waterfall

```

## Usage

```js

import pWaterfall from 'p-waterfall';

const tasks = [

	initialValue => getEmoji(initialValue),

	previousValue => `I ❤️ ${previousValue}`

];

console.log(await pWaterfall(tasks, 'unicorn'));

//=> 'I ❤️ 🦄'

```

## API

### pWaterfall(tasks, initialValue?)

Returns a `Promise` that is fulfilled when all promises returned from calling the functions in `tasks` are fulfilled, or rejects if any of the promises reject. The fulfilled value is the value returned from the last task.

#### tasks

Type: `Iterable`

Functions are expected to return a value. If a `Promise` is returned, it's awaited before continuing with the next task.

#### initialValue

Type: `unknown`

Value to use as `previousValue` in the first task.

## Related

- [p-series](https://github.com/sindresorhus/p-series) - Run promise-returning & async functions in series

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

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

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