ifenv

ifenv is a tiny preprocessor for JavaScript loosely modelled after C. It can be used on its own or as a webpack loader. Its main purpose is to remove content from source files based on environment variables.

directives

#ifenv

// #ifenv NAME

Will copy all consecutive lines until encountering #endif only if NAME is set in your environment. Will only check if the variable is set and not the value.

Consider the following input:

doSomething();
// #ifenv DEV
console.log('did something...');
// #endif
doSomethingElse();

Which if DEV is set, produces the following output:

doSomething();
console.log('did something...');
doSomethingElse();

Otherwise:

doSomething();
doSomethingElse();

usage

Install the package using

npm install ifenv

webpack

After installation, you can just add it as a loader within your webpack config:

  module: {
    rules: [
      {
        test: /\.js$/,
        use: ['ifenv']
      }
    ]
  }