javascript - webpack loaders and include -

i'm new webpack , i'm trying understand loaders properties such test, loader, include etc.

here sample snippet of webpack.config.js found in google.

module: {     loaders: [       {         test: /\.js$/,         loader: 'babel-loader',         include: [           path.resolve(__dirname, 'index.js'),           path.resolve(__dirname, 'config.js'),           path.resolve(__dirname, 'lib'),           path.resolve(__dirname, 'app'),           path.resolve(__dirname, 'src')         ],         exclude: [           path.resolve(__dirname, 'test', 'test.build.js')         ],         cachedirectory: true,         query: {           presets: ['es2015']         }       },     ] } 

1. am right test: /.js$/ used files extension .js?

2. the loader: 'babel-loader', loader install using npm

3. the include: have many questions on this. right put inside array transpiled? means, index.js, config.js, , *.js files in lib, app , src transpiled.

4. more questions on include: when files transpiled, *.js files concatenated 1 big file?

5. i think exclude self explanatory. not transpiled.

6. what query: { presets: ['es2015'] } do?

in webpack config there multiple things configuration, important ones are

1. entry - can array or object defining entry point asset want bundle, can js test here says /.js$. application if has multiple entry points use array.
2. include - defines set of path or files imported files transformed loader.
3. exclude self explanatory (do not transform file these places).

4. output - final bundle want create. if specify example

   output: { filename: "[name].bundle.js", vendor: "react" }

   then application js files bundled main.bundle.js , react in vendor.js files. error if not use both in html page.

hope helped