tobimx / ignore-styles

Ignore imported style files when running in Node

ignore-styles

A babel/register style hook to ignore style imports when running in Node. This is for projects that use something like Webpack to enable CSS imports in JavaScript. When you try to run the project in Node (to test in Mocha, for example) you'll see errors like this:

SyntaxError: /Users/brandon/code/my-project/src/components/my-component/style.sass: Unexpected token (1:0)
> 1 | .title
| ^
2 |   font-family: serif
3 |   font-size: 10em
4 |

To resolve this, require ignore-styles with your mocha tests:

mocha --require ignore-styles

See DEFAULT_EXTENSIONS for the full list of extensions ignored, and send a pull request if you need more.

Note: This is not for use inside Webpack. If you want to ignore extensions in Webpack you'll want to use a loader like ignore-loader. This is for use in Node outside of your normal Webpack build.

Installation

$ npm install --save-dev ignore-styles

More Examples

To use this with multiple Mocha requires:

mocha --require babel-register --require ignore-styles

You can also use it just like babel/register:

import 'ignore-styles'

In ES5:

require('ignore-styles')

To customize the extensions used:

import register from 'ignore-styles'
register(['.sass', '.scss'])

To customize the extensions in ES5:

require('ignore-styles').default(['.sass', '.scss']);

Custom handler

By default, a no-op handler is used that doesn't actually do anything. If you'd like to substitute your own custom handler to do fancy things, pass it as a second argument:

import register from 'ignore-styles'
register(undefined, () => ({styleName: 'fake_class_name'}))

The first argument to register is the list of extensions to handle. Leaving it undefined, as above, uses the default list. The handler function receives two arguments, module and filename, directly from Node.

Why is this useful? One example is when using something like react-css-modules. You need the style imports to actually return something so that you can test the components, or the wrapper component will throw an error. Use this to provide test class names.

Another use case would be to simply return the filename of an image so that it can be verified in unit tests:

const _ = require('lodash');
const path = require('path');

register(undefined, (module, filename) => {
  if (_.some(['.png', '.jpg'], ext => filename.endsWith(ext))) {
    module.exports = path.basename(filename);
  }
})

If the filename ends in '.png' or '.jpg', then the basename of the file is returned as the value of the module on import.

License

The MIT License (MIT)

Copyright (c) 2015 Brainspace Corporation