https://github.com/preco21/pcancel

Wrap promise function into cancelable promise function
https://github.com/preco21/pcancel

cancel cancelable cancellation p promise

Last synced: 6 days ago
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Wrap promise function into cancelable promise function

• Host: GitHub
• URL: https://github.com/preco21/pcancel
• Owner: preco21
• License: mit
• Created: 2017-05-24T02:20:12.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2018-01-11T05:33:44.000Z (almost 7 years ago)
• Last Synced: 2024-10-30T16:11:57.943Z (16 days ago)
• Topics: cancel, cancelable, cancellation, p, promise
• Language: JavaScript
• Size: 40 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# pcancel

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> Wrap promise function into cancelable promise function

Sometimes you may need to create cancelable promise for situation like to avoid [isMounted antipattern in React](https://facebook.github.io/react/blog/2015/12/16/ismounted-antipattern.html). `pcancel` provides simple utility for creating cancelable promises. Highly inspired from [this comment](https://github.com/facebook/react/issues/5465#issuecomment-157888325).

## Install

```bash

$ npm install pcancel

```

## Usage

```javascript

import pcancel from 'pcancel';

const delayC = pcancel(delay);

const p = delayC(4000)

  .promise

  .then(() => console.log('Yey!'))

  .catch((err) => console.error(err));

p.cancel(); // Error: Promise has canceled

function delay(time) {

  return new Promise((resolve) => setTimeout(() => resolve(), time));

}

```

## API

### pcancel(fn[, options])

* `fn` Function - Promise-returning function that will be cancelable.

* `options` Object (optional)

  * `noReject` Boolean - Whether to reject when canceling. If this option is `true`, the promise will be resolved with the value passed through to `cancel()` method on the promise.

Returns a wrapped function that returns object includes `Promise` instance and `cancel()` function.

You can also specify error or value through `cancel()` method, the specified value will be returned instead of value of the promise:

```javascript

p.cancel(new Error('Foo')); // Error: Foo

```

**Note:** `cancel()` rejects the promise immediately when it called.

## License

[MIT](https://preco.mit-license.org/)