Running tests with Mocha - ES6 style

So you have an ES6 code base and you'd like to test it using Mocha? Let's do it!

npm install --save-dev mocha babel-register babel-preset-es2015
echo '{ "presets": [ "es2015" ] }' > .babelrc
mocha --compilers js:babel-register *.test.js

Easy, right?

Let's go through it line by line. In the first line we're installing mocha, the testing framework, babel-register which will enable babel transpiler and babel-preset-es2015 which is required for the es6-to-es5 transpilation.

Then in the second line we're creating a .babelrc file that will tell Babel how to transpile our code.

In the last line we're configuring Mocha to run our tests using Babel as the compiler for files with js extensions. It'll look for all files ending with .test.js and treat them as tests.

Happy testing!