Add support for new webpack 2 fields

[kentcdodds]

Here are a few:

{
    modules: [path.resolve(__dirname, "app"), "node_modules"]
    // (was split into `root`, `modulesDirectories` and `fallback` in the old options)
    // In which folders the resolver look for modules
    // relative paths are looked up in every parent folder (like node_modules)
    // absolute paths are looked up directly
    // the order is respected

    descriptionFiles: ["package.json", "bower.json"],
    // These JSON files are read in directories

    mainFields: ["main", "browser"],
    // These fields in the description files are looked up when trying to resolve the package directory

    mainFiles: ["index"]
    // These files are tried when trying to resolve a directory

    aliasFields: ["browser"],
    // These fields in the description files offer aliasing in this package
    // The content of these fields is an object where requests to a key are mapped to the corresponding value

    extensions: [".js", ".json"],
    // These extensions are tried when resolving a file

    enforceExtension: false,
    // If false it will also try to use no extension from above

    moduleExtensions: ["-loader"],
    // These extensions are tried when resolving a module

    enforceModuleExtension: false,
    // If false it's also try to use no module extension from above

    alias: {
        jquery: path.resolve(__dirname, "vendor/jquery-2.0.0.js")
    }
    // These aliasing is used when trying to resolve a module
}

[jonathanglasmeyer]

We should probably look the webpack version up by inspecting the package.json and then put it into the schemaOptions in order to switch behaviour.

[danielkcz]

Apart from changes mentioned above, there is also change to loader configuration.

Having loader like this fails with "1" must be a string

{ test: /\.css$/, include: srcPath, loaders: [
    'style',
    { loader: 'css', query: { modules: true }}
]},

[wclr]

I believe modules should be allowed in resolve and resolveLoader

[texastoland]

Apart from changes mentioned above, there is also change to loader configuration.

Also loaders is a synonym for loader used with query objects.

[sir-dunxalot]

Here's another example of webpack 2 incompatibility... The following webpack 2 config where loader isn't a string is valid. However, webpack-validator throws an error and says "loader" must be a string.

  module: {
    loaders: [
      {
        test: /\.scss$/,
        loader: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: [
            'css-loader?importLoaders=1&sourceMap',
            'postcss-loader',
            'resolve-url-loader',
            'sass-loader?sourceMap',
          ],
        }),
      }
    ]
  }

[kentcdodds]

Please note the README. We're not going to support Webpack 2