standard-as-callback

What is standard-as-callback?

The standard-as-callback npm package is designed to convert standard Node.js style callback functions into a format that can be used with promises. This is particularly useful when working with older Node.js APIs or third-party libraries that do not return promises natively. By wrapping these functions with standard-as-callback, developers can work with them using promise chains or async/await syntax, which can lead to cleaner and more maintainable code.

What are standard-as-callback's main functionalities?

Converting callback to promise

This feature allows you to convert a standard Node.js callback-style function into a promise. In the code sample, the fs.readFile function, which normally takes a callback, is converted into a promise-returning function using standard-as-callback. This allows for the use of .then() and .catch() for handling the asynchronous operation.

const standardAsCallback = require('standard-as-callback');
const fs = require('fs');

const readFilePromise = standardAsCallback(fs.readFile);

readFilePromise('example.txt', 'utf8').then(content => {
  console.log(content);
}).catch(error => {
  console.error(error);
});

Other packages similar to standard-as-callback

util.promisify

Built into Node.js, util.promisify converts a callback-based function into a promise-based one. It is similar to standard-as-callback but is a native utility, which means it does not require an additional package installation. It is widely used due to its availability in the Node.js standard library.

bluebird

Bluebird is a full-featured promise library that includes utilities for converting callback-based functions into promises. It offers a method called .promisify() which serves a similar purpose to standard-as-callback. Bluebird also provides a rich set of features for controlling flow and handling concurrency, which makes it more powerful but also larger in size compared to standard-as-callback.

pify

Pify is a lightweight promise utility that can convert functions using the Node.js callback pattern to return promises. It is similar to standard-as-callback but offers additional options for customizing the behavior of the promisified functions, such as the ability to promisify methods of an object or to exclude certain functions based on a filter.

README

Standard asCallback

A performant and standard (Bluebird) library that registers a node-style callback on a promise.

Install

$ npm install standard-as-callback

Usage

const asCallback = require('standard-as-callback')

const promise = new Promise(function (resolve) {
  setTimeout(function () {
    resolve('hello world!')
  }, 1000)
})

asCallback(promise, function callback (err, res) {
  console.log(err, res) // null, 'hello world!'
})

Thanks

Most code of this library are ported from the awesome Bluebird library.

License

The MIT License.