webpack-polyfilling

index.js

// 1.:

module.exports = {
  entry: './src/index.js'
}


// index.js
fetch = myFetch


// 2: 

module.exports = {
  entry: ['myCustomPolyfill', './src/index.js']
}


// myCustomPolyfill.js
fetch = myFetch


// 3: 

module.exports = {
  entry: './src/index.js',
  plugins: [
    new webpack.ProvidePlugin({
      fetch: 'something'
    })
  ]
}