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

While a condition returns true, calls a function repeatedly, and then resolves the promise
https://github.com/sindresorhus/p-whilst

Last synced: 3 days ago
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While a condition returns true, calls a function repeatedly, and then resolves the promise

• Host: GitHub
• URL: https://github.com/sindresorhus/p-whilst
• Owner: sindresorhus
• License: mit
• Created: 2015-11-17T17:48:47.000Z (about 9 years ago)
• Default Branch: main
• Last Pushed: 2024-10-16T14:39:19.000Z (3 months ago)
• Last Synced: 2025-01-18T07:07:10.539Z (10 days ago)
• Language: JavaScript
• Homepage:
• Size: 23.4 KB
• Stars: 54
• Watchers: 7
• Forks: 9
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: license

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• promise-fun - p-whilst

README

        
# p-whilst

> While a condition returns true, calls a function repeatedly, and then resolves the promise

Think async version of the [`while` statement](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/while).

## Install

```sh

npm install p-whilst

```

## Usage

```js

import pWhilst from 'p-whilst';

let count = 0;

await pWhilst(

	() => count < 5,

	() => count++

);

console.log(count);

//=> 5

```

## API

### pWhilst(condition, action, initialValue?)

While `condition` returns `true`, executes `action` repeatedly, and then resolves the promise to the result of the last call to `action`. Rejects if `action` returns a promise that rejects or if an error is thrown anywhere.

#### condition

Type: `Function`

Arguments: The value the `action` function returns or `initialValue` for the first iteration.

Expected to return a `boolean` or a `Promise` that indicates whether to execute `action`.

#### action

Type: `Function`

Arguments: The value the last call to `action` function returns.

Action to run for each iteration.

You can return a promise and it will be handled.

## Related

- [p-do-whilst](https://github.com/sindresorhus/p-do-whilst) - Calls a function repeatedly while a condition returns true and then resolves the promise

- [p-forever](https://github.com/sindresorhus/p-forever) - Run promise-returning & async functions repeatedly until you end it

- [p-wait-for](https://github.com/sindresorhus/p-wait-for) - Wait for a condition to be true

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