esm-rollup-combo 🙌🗞

Just ESM.js + Rollup.js FTW!!! 🙌 ლ(ಠ益ಠ)ლ

Summary

This NodeJS repository demonstrates the usage of ONLY:

• 🙌 ESM (ES Module Loader alternative to 'node --experimental-modules')
• 🗞 RollupJS (a damn better bundler than Webpack!!!!)

And you definitely DON'T NEED the following for pure NodeJS apps:

• ❌ BABEL!!! 😑👎
• ❌ WEBPACK!!! 😑👎

Background

So at the time of writing this (19 Dec 2018) NodeJS LTS was v10.14.2 which means ECMAScript 6 should just work right out of the box (we're talking 'import' and all ES6 goodness). So why the hell is it so difficult to get running? ლ(ಠ益ಠ)ლ

🤔 What about 'node --experimental-modules *.mjs'?

This works, except at the time of trying there was issues using Jestjs Testing which didn't acknowledge the *.mjs file extension and the hacks were horrendous which lead to a hunt for a sensible toolchain. So ended up reverting to a combination of:

• Mocha
• Chai (using Expect)
• Sinon test spies
• Moxios - Axios Mocks

!!!Yes this rant is all about getting testing to work!!!

!!!❌NO TESTS - ❌NO STRAIGHT TO PRODUCTION #s2p!!!

🤔 What happened to Babel & Webpack?

Definitely both useful tools for bundling frontend code and would spend the extra time to get it running (but DAMN are those tools FIDDLY!). Even after removing Jest & setting up Webpack 4 for bundling, there were issues with resultant app.bundle.js acknowledging the NODE_ENV with this project ('mode':'production' was set etc...), so not a smooth development experience.

However, for pure backend NodeJS apps with no frontend, those tools are not necessary when writing code in ES6. Instead we're going with the bare minimum, ESM & Rollup to bundle up our app

⚙️ Development Strategy - use ESM

ESM

npm install --save esm

package.json

  "scripts": {
    "develop": "node -r esm src/index.js",

⚙️ Production Strategy - use RollupJS to bundle

RollupJS (a damn better bundler than Webpack!!!!)

npm install --save-dev rollup rollup-plugin-node-resolve

package.json

"scripts": {
    "build": "rollup --config rollup.config.prod.js"

rollup.config.production.js

import resolve from "rollup-plugin-node-resolve";

export default {
    input: './src/index.js',
    output: [
        {
            file: './dist/app.bundle.js',
            format: 'cjs',
            sourceMap: true
        }
    ],
    plugins: [
        resolve({
            module: true,
            modulesOnly: true
        })
    ]
}

🤔 Could you use Rollup Develop builds instead of ESM?

Most definitely, just create a rollup.config.dev.js and have a filewatcher for continuous develop builds. I like ESM, it's quick and it works well 🙌

⚙️ NPM Commands

Install node_modules

npm install

Tests

npm test

Build

npm run build

Start

npm start

License

MIT