By Iliyan Peychev | October 18, 2017

Running an application on a specific version of Node.js

In case you are building a Node.js application and want to host it on WeDeploy, we have good news for you - now you can specify a designated version of Node.js.

Specifying Node.js version

This solves at least these two problems:

  1. You can use all the experimental features which Node.js has already, even if they are not available in the default version of Node.js which runs on WeDeploy.
  2. In case of a vulnerability, you can immediately update the Node.js version even before we update the default version.

To specify the designated version, you may use the standard engines property in your package.json. We honour npm's full syntax so the following will work just fine.

Specifying range:

  "engines": {
    "node": ">=8.4 <8.6"

Specifying a fixed version:

  "engines": {
    "node": "8.7.0"

Using ECMAScript 2015 modules

The recent versions of Node.js contain most of the modern features added to JavaScript. We can use classes, arrow functions, async/await and so on, which makes the life of a developer much easier.

However, till recently, we were still not able to use the import and export statements as specified by the language. Instead we either had to use require or to use transpilers, like Babel. Fortunately, an experimental implementation of ES2015 modules in Node was added recently. Let's see how can we use it.

To enable ES2015 modules support, you have to specify at least v8.5 of Node.js and run the program with --experimental-modules flag:

  "engine": {
    "node": ">=8.5.0"
  "scripts": {
    "start": "node --experimental-modules index.mjs"

To show an example of their usage, we created a sample project. You may see it live here. The full source code is available on Github.

The project shows how to import the three kind of modules: built-in Node modules, locally created modules and npm modules:

import http from 'http';
import hackerQuotes from 'hacker-quotes';
import {getRandomQuote} from './random-hacker-quotes.mjs';

No transpilers or complex build systems are used - just plain JavaScript.

Happy hacking!