webpack loaders. because you only want to write this -once-

loaders.js

module.exports = [
  {
    test: /\.jsx?$/,
    loader: 'babel',
  },
  {
    test: /\.css$/,
    loader: 'style-loader!css-loader',
  },
  {
    test: /\.json$/,
    loader: 'json-loader',
  },
  {
    test: /\.sass/,
    loader: 'style-loader!css-loader!sass-loader?outputStyle=expanded&indentedSyntax',
  },
  {
    test: /\.scss/,
    loader: 'style-loader!css-loader!sass-loader?outputStyle=expanded',
  },
  {
    test: /\.less/,
    loader: 'style-loader!css-loader!less-loader',
  },
  {
    test: /\.styl/,
    loader: 'style-loader!css-loader!stylus-loader',
  },
  {
    test: /\.(png|jpg|gif|woff|woff2)$/,
    loader: 'url-loader?limit=8192',
  },
  {
    test: /\.(mp4|ogg|svg)$/,
    loader: 'file-loader',
  }
];