@americanexpress/css-to-js

Tool for transforming CSS into JS

👩‍💻 Hiring 👨‍💻

Want to get paid for your contributions to CSS-to-JS?

Send your resume to [e-mail]

📖 Table of Contents

• Features
• Usage
• API
• Git Hooks
• Contributing

✨ Features

• Converts CSS to JS
• Supports multiple input and output formats (inline code, files, directories)
• Generates style objects as e6 exports with options to split into separate files
• Reverse media query distribution

🤹‍ Usage

Install:

npm install @americanexpress/css-to-js --save-dev  

CLI:

css-to-js <inputPath> <outputPath> (--mediaReverse) (--splitFile | --shakeFile)  
  
Arguments:  
 inputPath   input path to css file or dir of css files outputPath  output path to js file or dir  Options:  
 --help --version --mediaReverse  reverse mediaQuery style properties  --splitFile  generate multiple files with exports for each selector in css file   
  --shakeFile  generate single file with exports for each selector in css file   
    
  If shakeFile or splitFile is not specified, generate single file with single exported object with selectors in css file as keys  
 See API for more details.

Node:

import { convert } from 'css-to-js';  
Example Usage:   

//Input CSS string, Outputs JS Object  
convert(`.myClass { color: 'red' }`);   

//Input CSS string, Output file exporting JS Object  
convert(`.myClass { color: 'red' }`, { outputType: 'file', outputPath: 'outPath' });   

//Input CSS file path, Output file exporting JS Object  
convert('absolute-path-to-css-file', { outputType: 'file', outputPath: 'outPath' });  
  
//Input CSS file path, Output file exporting multiple JS Objects  
convert('absolute-path-to-css-file', { outputType: 'shakeFile', outputPath: 'outPath' });  
  
//Input CSS file path, Outputs dir of files exporting single JS Objects (If treeshaking not supported)  
convert('absolute-path-to-css-file', { outputType: 'splitFile', outputPath: 'outPath' });  
  
//Input Dir path of CSS files, Output array of JS Objects  
convert('absolute-path-to-dir');  
  
//Input Dir path of CSS files, Output dir of converted files exporting JS Object  
convert('absolute-path-to-dir'', { outputType: 'file', outputPath: 'outPath' });  
  

🎛️ API

Input and Output type options

Ensure paths are absolute or relative to the root only

Convert Function	Input Type	Output Type(s)
convert(css);	Path to single CSS file or string of CSS code	JS style object
convert(css, { outputType: 'file', outputPath: 'example.js' });	Path to single CSS file or string of CSS code	Generated JS file 'example.js' with a default export of a JS style object
convert(css, { outputType: 'shakeFile', outputPath: 'shakeExample.js' });	Path to single CSS file or string of CSS code	Generated JS file 'shakeExample.js' with multiple named exports of JS style objects
convert(css, { outputType: 'splitFile', outputPath: 'splitExample' });	Path to single CSS file or string of CSS code	Generated directory 'splitExample' with multiple files each with a default export of a JS style object
convert(dirPath);	Path to directory of CSS files	Array of JS style objects
convert(dirPath, { outputType: 'file', outputPath: 'exampleDir' });	Path to directory of CSS files	Generated directory of JS files; Each file has a default export of a JS style object and is named after the corresponding css file
convert(dirPath, { outputType: 'shakeFile', outputPath: 'shakeExample.js' });	Path to directory of CSS files	Generated directory of JS files; Each file has multiple named exports of JS style objects and is named after the corresponding css file
convert(dirPath, { outputType: 'splitFile', outputPath: 'splitExample' });	Path to directory of CSS files	Generated directory of directories; Each file has a default export of a JS style object and is named after the corresponding css file

File conversion examples

Sample Input: nav.css

.class1 {    
  color: 'red';  
}  
.class2 {
  color: 'blue'; 
}

---

Example 1: File - Creates a file with a single object export representing tree of full converted css

convert(
   path.resolve(__dirname, './nav.css'), 
   { 
     outputType: 'file', 
     outputPath: path.resolve(__dirname, '../example1.js') 
   }
);

Output: Example1.js

export default {   
  class1: { color: 'red' },   
  class2: { color: 'blue' } 
}  

---

Example 2: ShakeFile - Create file with multiple exports representing each selector of converted css
(Useful for tree-shaking style objects that do not get used)

convert(
   path.resolve(__dirname, './nav.css'), 
   { 
     outputType: 'shakeFile', 
     outputPath: path.resolve(__dirname, '../example2.js') 
   }
);

Output: Example2.js

export const class1 = { color: 'red' };  
export const class2 = { color: 'blue' };  

---

Example 3: SplitFile - Create multiple files with exports representing each selector of converted css
(Useful for excluding style objects that do not get used if tree-shaking is not implemented)

convert(
   path.resolve(__dirname, './nav.css'), 
   { 
     outputType: 'splitFile', 
     outputPath: path.resolve(__dirname, '../example3') 
   }
);

Output: Example3/

class1.js

export default { color: 'red' };  

class2.js

export default { color: 'blue' }; 

Media Reverse

Note: mediaReverse is always true if output type is shakeFile or splitFile

Sometimes it's useful to have the styles located in media queries distributed into the selector properties rather than be their own property.
If the mediaReverse flag is set to true, reverse the positioning of media queries to be inside the property.

nav.css

.class1 { color: 'red'; }  
  
@media (min-width:500px) {    
  .class1 { color: 'blue'; } 
}  
@media (min-width:1000px) {    
  .class1 { color: 'green'; } 
}  

If mediaReverse is not set:

convert(
   path.resolve(__dirname, './nav.css'), 
   { 
     outputType: 'file', 
     outputPath: path.resolve(__dirname, '../example4.js') 
   }
);

Example4.js

export default {   
  class1: { color: 'red' },   
  '@media (min-width:500px)': {  
    class2: { color: 'blue' }   
  },  
  '@media (min-width:1000px)': {
    class2: { color: 'green' }   
  }  
}  

If mediaReverse is set to true:

convert(
   path.resolve(__dirname, './nav.css'), 
   { 
     outputType: 'file', 
     outputPath: path.resolve(__dirname, '../example4.js'),
     mediaReverse: true 
   }
);

Example4.js

export default {   
 class1: { color: 'red' },   
 class2: {   
   '@media (min-width:500px)': {  
     color: 'blue'   
   },  
   '@media (min-width:1000px)': {
     color: 'green'   
   }    
 }  
}  

🎣 Git Hooks

These commands will be automatically run during normal git operations like committing code.

pre-commit

This hook runs npm test before allowing a commit to be checked in.

commit-msg

This hook verifies that your commit message matches the One Amex conventions. See the commit
message section in the CONTRIBUTING.md.

🏆 Contributing

We welcome Your interest in the American Express Open Source Community on Github. Any Contributor to any Open Source Project managed by the American Express Open Source Community must accept and sign an Agreement indicating agreement to the terms below. Except for the rights granted in this Agreement to American Express and to recipients of software distributed by American Express, You reserve all right, title, and interest, if any, in and to Your Contributions. Please fill out the Agreement.

Please feel free to open pull requests and see CONTRIBUTING.md for commit formatting details.

🗝️ License

Any contributions made under this project will be governed by the Apache License 2.0.

🗣️ Code of Conduct

This project adheres to the American Express Community Guidelines.
By participating, you are expected to honor these guidelines.