Local debug Webpack application

When I run webpack serve --port 8080 --open --config webpack.dev.js --static-directory www, it serves the files from www at https://localhost:8080. However, it does not build the entry-point JavaScript. Why?

I’m having to explicitly run webpack -c webpack.dev.js before webpack serve. Is there a way to run it in parallel with webpack serve while also watching for changes?

webpack.common.js:

const path = require('path');

module.exports = {
  entry: './src/main.ts',
  output: {
    path: path.resolve(__dirname, 'www/res/js/build'),
    publicPath: path.resolve(__dirname, 'www/res/js/build'),
    filename: 'main.js',
  },
  // ...
}