Setting up Babel

Now webpack knows that it should compile JavaScript files with Babel, but we haven't even set up Babel yet! To do so perform the following steps:

First, let's install the Babel-related libraries:

npm install --save-dev babel-core babel-loader babel-preset-es2015
npm install --save-dev babel-plugin-transform-object-rest-spread

The preceding command includes babel-core, babel-loader for webpack, and the babel-preset for ES2015. We also installed the object rest/spread plugin, as it allows us to use rest/spread syntax with objects in addition to arrays. We will learn more about the rest/spread syntax later.

We still need to tell Babel which presets and plugins it should load. So, we will create a .babelrc file with the following content:

{
  "presets":[ "es2015" ],
  "plugins": [ "transform-object-rest-spread" ]
}

You can find more information about the Babel configuration on their API documentation page, at https://babeljs.io/docs/usage/api/#options.