What’s new for Node.js in 2020

In 2019, Node.js turned 10 years old, and the number of packages available on npm crossed one million. Downloads for Node.js itself continues to rise, growing 40% year over year. Another significant milestone is Node.js recently joined the OpenJS Foundation, which promises to improve project health and sustainability, as well as improve collaboration with the JavaScript community at large.

What’s new in Node.js Version 13?

As of this writing, the most recent release of Node.js is 13. There are already a number of features and updates we can start playing around with leading into 2020. Here’s a list of highlights:

• ECMAScript modules
• WebAssembly support
• Full internationalization support for date, time, number, and currency formats

Before we dive into the details of these updates, let’s take a look at what we can expect from the Node.js release schedule.

The Node.js release process for 2020

Major Node.js versions enter Current release status for six months, which gives library authors time to add support for them. After six months, odd-numbered releases (9, 11, etc.) become unsupported, and even-numbered releases (10, 12, etc.) move to Active LTS status and are ready for general use. LTS release status is “long-term support”, which typically guarantees that critical bugs will be fixed for a total of 30 months. Production applications should only use Active LTS or Maintenance LTS releases.

Support for ECMAScript modules

As of v13.2.0, Node.js supports both traditional CommonJS modules and the new standard ECMAScript (ES) modules out of the box. This means you can finally use import and export syntax you may already be using for client-side JavaScript running in the browser. Also, it’s important to note ES modules in Node.js have JavaScript strict mode enabled by default, so you don’t have to specify “use strict”; at the top of every file.

// message file
async function sendMessage { ... }
export { sendMessage };

// index file
import { sendMessage } from "./message";

However, you still need to do a little work to let Node.js know you are using ES modules. The two most common ways to do this are using the .mjs file extension or specifying “type”: “module” in the nearest parent package.json file.

• Option 1: Rename .js files to .mjs files.
• Option 2: Update the root package.json file, or add a package.json to the folder that contains ES modules and specify the type as module.

{
   "type": "module"
}

Another possibility is enabling ES module in the root package.json file, and then renaming all CommonJS module files to use the .cjs extension.

Personally, I find the .mjs and .cjs extensions a little gross, so I’m glad to see there are ways of specifying ES and CommonJS module usage with a package.json file.

Node.js can import WebAssembly modules

Along with ES module support comes the ability to import WebAssembly (Wasm) modules! A WebAssembly module is a portable compiled binary format that can be parsed faster than JavaScript and executed at native speeds. WebAssembly modules can be created using a language such as C/C++, Go, C#, Java, Python, Elixir, Rust, and many others.

WebAssembly module support is still in the experimental stage as of this writing. To enable the feature, you must pass a command-line flag when executing a Node.js application. For example:

node --experimental-wasm-modules index.js

As an example, imagine you have an image processing library implemented as a WebAssembly module. The syntax for using this Wasm module might look like the following.

import * as imageUtils from "./imageUtils.wasm";
import * as fs from "fs";
( async () => {
   const image = await fs.promises.readFile( "./image.png" );
   const updatedImage = await imageUtils.rotate90degrees( image );
} )();

It’s also possible to import a WebAssembly module using the new dynamic import() statement in Node.js

"use strict";
const fs = require("fs");
( async () => {
   const imageUtils = await import( "./imageUtils.wasm" );
   const image = await fs.promises.readFile( "./image.png" );
   const updatedImage = await imageUtils.rotate90degrees( image );
} )();

WebAssembly System Interface (WASI)

Similar to JavaScript, WebAssembly is designed with security in mind to prevent access to any of the underlying operating system, sometimes referred to as “sandboxed.” However, there are times when a WebAssembly module in your control in Node.js may benefit from being able to make system-level calls.

This is where the new WebAssembly System Interface (WASI) comes in. WASI is designed to be a standard interface for making calls to the underlying system, such as the host application, native operating system, and so forth.

Initial WASI support was recently committed to the Node.js project. WASI is another exciting feature we may see come to Node.js in 2020!

Internationalization support expands in 2020

As of v13.x, Node.js comes compiled with full ICU (International Components for Unicode). ICU is a mature and popular globalization library. Among many features, ICU includes support for formatting numbers, dates, times and currencies, performing time calculations and string comparisons, and converting text between Unicode and other character sets.