READMEeng.md

5 - The ES6 modules syntax

Here we simply replace const Dog = require('./dog') by import Dog from './dog', which is the newer ES6 modules syntax (as opposed to "CommonJS" modules syntax).

In dog.js, we also replace module.exports = Dog by export default Dog.

Note that in dog.js, the name Dog is only used in the export. Therefore it could be possible to export directly an anonymous class like this instead:

export default class {
  constructor(name) {
    this.name = name;
  }

  bark() {
    return `Wah wah, I am ${this.name}`;
  }
}

You might now guess that the name 'Dog' used in the import in index.js is actually completely up to you. This would work just fine:

import Cat from './dog';

const toby = new Cat('Toby');

Obviously, most of the time you will use the same name as the class / module you're importing. A case where you don't do that is how we const babel = require('gulp-babel') in our Gulp file.

So what about those require()s in our gulpfile.js? Can we use import instead? The latest version of Node supports most ES6 features, but not ES6 modules yet. Luckily for us, Gulp is able to call Babel for help. If we rename our gulpfile.js to gulpfile.babel.js, Babel will take care of passing imported modules to Gulp.

• Rename your gulpfile.js to gulpfile.babel.js

• Replace your require()s by:

import gulp from 'gulp';
import babel from 'gulp-babel';
import del from 'del';
import { exec } from 'child_process';

Note the syntactic sugar to extract exec directly from child_process. Pretty elegant!

• yarn start should still print "Wah wah, I am Toby".

Next section: 6 - ESLint

Back to the previous section or the table of contents.