asyncpify
v4.0.3
Published
Convert a callback-style function to an AsyncFunction
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asyncpify
Convert a callback-style function to an AsyncFunction
Install
$ npm install asyncpify
Usage
const fs = require('fs');
const asyncpify = require('asyncpify');
// Promisify a single function
asyncpify(fs.readFile)('package.json', 'utf8').then(data => {
console.log(JSON.parse(data).name);
//=> 'asyncpify'
});
// Promisify all methods in a module
asyncpify(fs).readFile('package.json', 'utf8').then(data => {
console.log(JSON.parse(data).name);
//=> 'asyncpify'
});
API
asyncpify(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 asyncpify = require('asyncpify');
asyncpify(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 asyncpify = require('asyncpify');
function fn() {
return true;
}
fn.method = (data, callback) => {
setImmediate(() => {
callback(null, data);
});
};
// Promisify methods but not `fn()`
const promiseFn = asyncpify(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
- pify - Promisify a callback function. This project is a
pify
fork.
License
MIT © Sindre Sorhus