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instapromise

Instapromise Circle CI

Promisify Node-style asynchronous functions by putting a .promise after them (or after the object for methods).

npm package

If you use this library then if you put .promise after a Node-style asynchronous function, it will turn it into a function that returns a promise instead of taking a callback.

import 'instapromise';
import fs from 'fs';
 
let p = fs.readFile.promise('/tmp/hello', 'utf8');
p.then(console.log);

The original function is available as a property on the promise-generating function (.___instapromiseOriginalFunction___).

If you want to promisify methods, use .promise after the object and before the method name.

import 'instapromise';
import fs from 'fs';
 
let p = fs.promise.readFile('/tmp/hello', 'utf8');
p.then(console.log);

Changelog

2.0.7

Non-enumerable properties like class methods are now promisified. Functions with names that would cause syntax errors (like default) are supported.

2.0.3

The ___instapromiseOriginalFunction___ property is now non-enumerable so it doesn't show up when serializing functions whose promise property has been accessed before.

2.0.0

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.

Credits

This code is based on the proxying code used in fibrous.