Nauseating Packaged Meat

    pify
    TypeScript icon, indicating that this package has built-in type declarations

    2.3.0 • Public • Published

    pify Build Status

    Promisify a callback-style function

    Install

    $ npm install --save pify
    

    Usage

    const fs = require('fs');
    const pify = require('pify');
    
    // promisify a single function
    
    pify(fs.readFile)('package.json', 'utf8').then(data => {
    	console.log(JSON.parse(data).name);
    	//=> 'pify'
    });
    
    // or promisify all methods in a module
    
    pify(fs).readFile('package.json', 'utf8').then(data => {
    	console.log(JSON.parse(data).name);
    	//=> 'pify'
    });

    API

    pify(input, [promiseModule], [options])

    Returns a promise wrapped version of the supplied function or module.

    input

    Type: function, object

    Callback-style function or module whose methods you want to promisify.

    promiseModule

    Type: function

    Custom promise module to use instead of the native one.

    Check out pinkie-promise if you need a tiny promise polyfill.

    options

    multiArgs

    Type: boolean
    Default: false

    By default, the promisified function will only return the second argument from the callback, which works fine for most APIs. This option can be useful for modules like request that return multiple arguments. Turning this on will make it return an array of all arguments from the callback, excluding the error argument, instead of just the second argument.

    const request = require('request');
    const pify = require('pify');
    
    pify(request, {multiArgs: true})('https://sindresorhus.com').then(result => {
    	const [httpResponse, body] = result;
    });
    include

    Type: array of (string|regex)

    Methods in a module to promisify. Remaining methods will be left untouched.

    exclude

    Type: array of (string|regex)
    Default: [/.+Sync$/]

    Methods in a module not to promisify. Methods with names ending with 'Sync' are excluded by default.

    excludeMain

    Type: boolean
    Default: false

    By default, if given module is a function itself, this function will be promisified. Turn this option on if you want to promisify only methods of the module.

    const pify = require('pify');
    
    function fn() {
    	return true;
    }
    
    fn.method = (data, callback) => {
    	setImmediate(() => {
    		callback(data, null);
    	});
    };
    
    // promisify methods but not fn()
    const promiseFn = pify(fn, {excludeMain: true});
    
    if (promiseFn()) {
    	promiseFn.method('hi').then(data => {
    		console.log(data);
    	});
    }

    License

    MIT © Sindre Sorhus

    Install

    npm i pify@2.3.0

    Version

    2.3.0

    License

    MIT

    Last publish

    Collaborators

    • sindresorhus