46 lines
1.7 KiB
Markdown
46 lines
1.7 KiB
Markdown
# Instapromise [](https://circleci.com/gh/exponentjs/instapromise)
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Promisify Node-style asynchronous functions by putting a `.promise` after them (or after the object for methods).
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[](https://nodei.co/npm/instapromise/)
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If you use this library then if you put `.promise` after a Node-style
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asynchronous function, it will turn it into a function that returns a promise
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instead of taking a callback.
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```js
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import 'instapromise';
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import fs from 'fs';
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let p = fs.readFile.promise('/tmp/hello', 'utf8');
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p.then(console.log);
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```
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The original function is available as a property on the promise-generating function (`.___instapromiseOriginalFunction___`).
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If you want to promisify methods, use `.promise` after the object and before the method name.
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```js
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import 'instapromise';
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import fs from 'fs';
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let p = fs.promise.readFile('/tmp/hello', 'utf8');
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p.then(console.log);
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```
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## Changelog
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### 2.0.7
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Non-enumerable properties like class methods are now promisified.
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Functions with names that would cause syntax errors (like `default`) are supported.
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### 2.0.3
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The `___instapromiseOriginalFunction___` property is now non-enumerable so it doesn't show up when serializing functions whose `promise` property has been accessed before.
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### 2.0.0
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The `Promise` polyfill is no longer provided. 1.x provided a polyfill for environments without a native `Promise` implementation, but in general, most environments you'll use now provide `Promise`.
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## Credits
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This code is based on the proxying code used in [fibrous](https://github.com/goodeggs/fibrous/blob/master/src/fibrous.coffee).
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