macro-preprocessor-loader v0.0.3

macro-preprocessor-loader

The C preprocessor or cpp is the macro preprocessor for the C and C++ computer programming languages. The preprocessor provides the ability for the inclusion of header files, macro expansions, conditional compilation, and line control.

Installation

npm install --save-dev macro-preprocessor-loader

Usage

webpack.config.js

Put the macro-preprocessor-loader as the last loader in the array, so it processes the code before all others.

module: {
  rules: [{
    test: /\.js$/,
    use: ['babel-loader', 'macro-preprocessor-loader']
  }]
}

Supported directives

• #if
• #else
• #elif
• #endif

On your code

Use //#if expression and //#endif to wrap blocks of code you want to be removed if a given prediction is false.

//#if process.env.NODE_ENV === 'DEVELOPMENT'
console.log('lorem')
console.log('ipsum')
//#endif

In the example above, the code will be removed if the enviroment variable NODE_ENV is not DEVELOPMENT, removing unnecessary code from your production bundle.

The same technique can be used to prevent loading packages in the production bundle.

// #if process.env.NODE_ENV !== 'BUILD'
import reduxLogger from 'redux-logger'
// #endif

Credits

• GCC C conditional documentation
• webpack-conditional-loader