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js-to-styles-var-loader-by-import

1.1.2 • Public • Published

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js-to-styles-var-loader

A Webpack loader to share variable data between javascript modules and sass or less files

This loader is for that special case when you would like to import data from a javascript module into a sass /less file. The sass / less loader complains, because importing js module is not a valid instruction.

The loader only handles the case when you want to inject variable data into a sass / less file via a javascript module.

Prerequisites

  • Nodejs >= 4.0
  • Webpack for module bundling

Setting up Webpack config

Probably you use sass-loader or less-loader with Webpack. The usage in this case is pretty simple: just put the js-to-styles-var-loader before the sass-loader / less-loader in your webpack config:

For sass-loader:

{
  rules: [
    test: /\.scss$/,
    use: [
      {
        loader: "style-loader"
      },
      {
        loader: "css-loader"
      },
      {
        loader: "sass-loader"
      },
      {
        loader: "js-to-styles-var-loader"
      }
    ]
  ]
}

For less-loader:

{
  rules: [
    test: /\.less$/,
    use: [
      {
        loader: "style-loader"
      },
      {
        loader: "css-loader"
      },
      {
        loader: "less-loader"
      },
      {
        loader: "js-to-styles-var-loader"
      }
    ]
  ]
}

Usage

Let's assume we would like to store some variable data in a module like this:

// colors.js
 
const colors = {
  'fancy-white': '#FFFFFE',
  'fancy-black': '#000001'
};
 
module.exports = colors;

You can use this module in your favorite templates / frameworks etc., and you don't want to repeat yourself when using these colors in a sass file as variable (e.g. $fancy-white: #FFFFFE; /*...*/ background-color: $fancy-white). In this situation just require your module in the beginning of your sass module:

require('relative/path/to/colors.js');
 
// ...
.some-class {
  background-color: $fancy-white
}
// ...

The form of the required data is important: it must be an object with key/values pair, the key will be the name of the variable.

The js-to-styles-var-loader transforms this sass file and provides it in the following form for the sass-loader:

$fancy-white: #FFFFFE;
$fancy-black: #000001;
 
.some-class {
  background-color: $fancy-white
}

Misc

You can import from named exports and properties of those, although the value of these must still be a flat list:

// themes.js
 
module.exports = {
  themes: {
    blue_theme: {
      some_color: "#00f"
    },
    red_theme: {
      some_color: "#f00"
    }
  },
  default: {
    some_color: "#aaa"
  }
};

Variables definitions are inserted into your sass/less file in place of the require() statement, so you can override variables inside blocks:

 
require("themes.js").default;
 
.someThing {
  color: @some_color;
}
 
.theme-blue {
  require("themes.js").themes.blue_theme;
 
  .someThing {
    color: @some_color;
  }
}
 
 

Demo

You can try the loader via a small fake app in the demo folder:

cd demo
npm i
npm run demo

The webpack dev server serves the app on localhost:8030. In the app we share data between js, less and sass modules.

Development

Run tests with npm test or npm run test:watch.

The transformer is developed with tdd, so if you would like to contribute, please, write your tests for your new functionality, and send pull request to integrate your changes.

Install

npm i js-to-styles-var-loader-by-import

DownloadsWeekly Downloads

51

Version

1.1.2

License

ISC

Unpacked Size

26.4 kB

Total Files

28

Last publish

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