mz

What is mz?

The mz npm package provides promisified versions of core Node.js modules such as fs (filesystem), child_process, and others. It wraps these Node.js core modules in promises, thus allowing developers to use async/await syntax for cleaner and more readable asynchronous code. This package is particularly useful for avoiding callback hell and improving code maintainability.

What are mz's main functionalities?

File System Operations

This feature allows for performing file system operations like reading, writing, and deleting files asynchronously using promises. The code sample demonstrates reading a file asynchronously with async/await syntax.

const fs = require('mz/fs');

async function readFile() {
  try {
    const content = await fs.readFile('/path/to/file.txt', 'utf8');
    console.log(content);
  } catch (err) {
    console.error(err);
  }
}

readFile();

Executing Child Processes

This feature enables the execution of child processes asynchronously. The code sample shows how to list files in the current directory using the `ls -la` command in a child process, leveraging async/await for handling the asynchronous execution.

const exec = require('mz/child_process').exec;

async function listFiles() {
  try {
    const stdout = await exec('ls -la');
    console.log(stdout);
  } catch (err) {
    console.error(err);
  }
}

listFiles();

Other packages similar to mz

fs-extra

fs-extra is a package that builds on the Node.js fs module, providing additional file system methods not found in the standard library. It supports both callback and promise-based APIs, making it a versatile choice for file operations. Compared to mz, fs-extra focuses more on extending the fs module's capabilities rather than promisifying existing ones.

execa

execa is a package designed to handle child processes more easily. It provides a promise-based interface, making it simpler to work with asynchronous process execution. execa offers more detailed control over child processes and better error handling compared to the child_process module wrapped by mz.

README

MZ - Modernize node.js

Modernize node.js to current ECMAScript specifications! node.js will not update their API to ES6+ for a while. This library is a wrapper for various aspects of node.js' API.

Installation and Usage

Set mz as a dependency and install it.

npm i mz

Then prefix the relevant require()s with mz/:

var fs = require('mz/fs')

fs.exists(__filename).then(function (exists) {
  if (exists) // do something
})

Personally, I use this with generator-based control flow libraries such as co so I don't need to use implementation-specific wrappers like co-fs.

var co = require('co')
var fs = require('mz/fs')

co(function* () {
  if (yield fs.exists(__filename)) // do something
})()

Promisification

Many node methods are converted into promises. Any properties that are deprecated or aren't asynchronous will simply be proxied. The modules wrapped are:

• child_process
• crypto
• dns
• fs
• zlib

var exec = require('mz/child_process').exec

exec('node --version').then(function (stdout) {
  console.log(stdout)
})

Promise Engine

If you've installed bluebird, bluebird will be used. mz does not install bluebird for you.

Otherwise, if you're using a node that has native v8 Promises (v0.11.13+), then that will be used.

Otherwise, this library will crash the process and exit, so you might as well install bluebird as a dependency!

FAQ

Can I use this in production?

If you do, you should probably install bluebird as native v8 promises are still pretty raw.

Will this make my app faster?

Nope, probably slower actually.

Can I add more features?

Sure. Open an issue.

Currently, the plans are to eventually support:

• ECMAScript7 Streams