Skip to content

mikehall314/es6-promisify

main
Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
Code

Files

Permalink
Failed to load latest commit information.

Build Status

es6-promisify

Converts callback-based functions to Promises, using a boilerplate callback function.

Install

Install with npm

npm install es6-promisify

Example

const {promisify} = require("es6-promisify");

// Convert the stat function
const fs = require("fs");
const stat = promisify(fs.stat);

// Now usable as a promise!
try {
    const stats = await stat("example.txt");
    console.log("Got stats", stats);
} catch (err) {
    console.error("Yikes!", err);
}

Promisify methods

const {promisify} = require("es6-promisify");

// Create a promise-based version of send_command
const redis = require("redis").createClient(6379, "localhost");
const client = promisify(redis.send_command.bind(redis));

// Send commands to redis and get a promise back
try {
    const pong = await client.ping();
    console.log("Got", pong);
} catch (err) {
    console.error("Unexpected error", err);
} finally {
    redis.quit();
}

Handle multiple callback arguments, with named parameters

const {promisify} = require("es6-promisify");

function test(cb) {
    return cb(undefined, 1, 2, 3);
}

// Create promise-based version of test
test[promisify.argumentNames] = ["one", "two", "three"];
const multi = promisify(test);

// Returns named arguments
const result = await multi();
console.log(result); // {one: 1, two: 2, three: 3}

Provide your own Promise implementation

const {promisify} = require("es6-promisify");

// Now uses Bluebird
promisify.Promise = require("bluebird");

const test = promisify(cb => cb(undefined, "test"));
const result = await test();
console.log(result); // "test", resolved using Bluebird

Tests

Test with tape

$ npm test

Published under the MIT License.