Why is a Vue.js project not being built by webpack?

Question

webpack

The following error occurs while building the project:

Package.json:

I installed all the loaders, but it seems to me that something is missing, the bundler simply does not recognize Vue files.
app.vue :

Answer 1

webpack.config.js

...
  module: {
    loaders: [
      {
        test: /\.vue$/,
        loader: 'vue-loader',
        exclude: [/node_modules/],
        options: {
          loaders: {
            scss: 'vue-style-loader!css-loader!sass-loader',
            sass: 'vue-style-loader!css-loader!sass-loader?indentedSyntax'
          }
        }
      },
...