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    @justinbeckwith/pify

    3.0.2 • Public • Published

    pify Build Status

    Promisify a callback-style function

    Install

    $ npm install 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'
    });
    
    // Promisify all methods in a module
    pify(fs).readFile('package.json', 'utf8').then(data => {
    	console.log(JSON.parse(data).name);
    	//=> 'pify'
    });

    API

    pify(input, [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.

    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. This also applies to rejections, where it returns an array of all the callback arguments, including the error.

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

    Type: string[] RegExp[]

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

    exclude

    Type: string[] RegExp[]
    Default: [/.+(Sync|Stream)$/]

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

    excludeMain

    Type: boolean
    Default: false

    If given module is a function itself, it 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(null, data);
    	});
    };
    
    // Promisify methods but not `fn()`
    const promiseFn = pify(fn, {excludeMain: true});
    
    if (promiseFn()) {
    	promiseFn.method('hi').then(data => {
    		console.log(data);
    	});
    }
    errorFirst

    Type: boolean
    Default: true

    Whether the callback has an error as the first argument. You'll want to set this to false if you're dealing with an API that doesn't have an error as the first argument, like fs.exists(), some browser APIs, Chrome Extension APIs, etc.

    promiseModule

    Type: Function

    Custom promise module to use instead of the native one.

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

    Related

    • p-event - Promisify an event by waiting for it to be emitted
    • p-map - Map over promises concurrently
    • More…

    License

    MIT © Sindre Sorhus

    Install

    npm i @justinbeckwith/pify

    DownloadsWeekly Downloads

    2

    Version

    3.0.2

    License

    MIT

    Unpacked Size

    6.83 kB

    Total Files

    4

    Last publish

    Collaborators

    • justinbeckwith