Compatible Runners | |
---|---|
Test Runners |
Table of Contents
Description
Babel is the leading tool to compile EcmaScript 2015+ to EcmaScript 5, combined with ESLint to lint your code, you get the best preset to get started.
Features
@swissquote/crafty-preset-babel
is able to configure Babel with Webpack. This preset also supports Gulp but in this case it concatenates and minifies the files, it doesn’t resolve imports.
Linting
In @swissquote/crafty-preset-babel
JavaScript is linted with ESLint, a powerful linter that supports plugins, our configuration follows the Swissquote JavaScript Guideline through our @swissquote/crafty-preset-eslint
preset.
Installation
npm install @swissquote/crafty-preset-babel --save
module.exports = {
presets: [
"@swissquote/crafty-preset-babel",
"@swissquote/crafty-runner-webpack", // optional
"@swissquote/crafty-runner-gulp" // optional
],
js: {
app: {
runner: "webpack", // Webpack or Gulp (optional if you have a single runner defined)
source: "js/app.js"
}
}
};
Usage
With Webpack
Both runners have the same features in regards to Babel support. They will resolve your modules recursively and bundle them in one file or more if you do some code-splitting.
JavaScript External assets
By default, all bundlers include all external dependencies in the final bundle, this works fine for applications, but if you wish to build a multi-tenant application or a library, you don’t wish to include all dependencies, because you’ll end up with the same dependency duplicated.
The externals
option allows you to define a list of libraries that are provided and should not be embedded in the build, here is an example :
module.exports = {
...
// patterns are strings or globs
externals: ["react", "react-dom", "squp", "squp/**"],
...
js: {
app: {
// You can provide more items here, they will be merged with the main list for this bundle
externals: ["my-plugin", "my-plugin/**"]
...
}
}
...
}
In this example react
, react-dom
and all modules starting with squp/
will be treated as external
With Gulp
Gulp will not bundle your files like Webpack does, instead it will generate one output file per input file. This is useful if you are creating a library as it’s the role of the final application to tree-shake what it doesn’t need from your library.
Tree-shaking is powerful but is sub-optimal on big files as some code patterns are recognized as side-effects and thus aren’t removed from your bundle even if they aren’t used.
Usage with Jest
If you include both crafty-preset-babel
and crafty-preset-jest
.
When running your tests with crafty test
this preset will be use to convert all .js
and .jsx
files (source and test files)
Configuration
Bundle options
Option | Type | Optional ? | Runner | Description |
---|---|---|---|---|
concat |
Boolean | Yes | Gulp | This will merge all files together, outputting a single file. (This doesn’t resolve imports, use Webpack for this) |
Adding Babel plugins and presets
You can add, replace or remove plugins and add options to our default Babel configuration. To see which plugins are already included, you can go to the Swissquote Preset for Babel page.
module.exports = {
/**
* Represents the extension point for Babel configuration
* @param {Crafty} crafty - The instance of Crafty.
* @param {Object} bundle - The bundle that is being prepared for build (name, input, source, destination)
* @param {Object} babelConfig - The current Babel configuration
*/
babel(crafty, bundle, babelConfig) {
babelConfig.plugins.push(
require.resolve("@babel/plugin-transform-property-literals")
);
}
};
After you did npm install --save-dev babel-plugin-transform-es5-property-mutators
before, Babel will now use this plugin as well in each run.
This method is called once per bundle, so you can customize each bundle’s configuration differently.