webpack

编写代码

app.js

import bar from './bar';

bar();

bar.js

export default function bar() {
  //
}

webpack.config.js

module.exports = {
  entry: './app.js',
  output: {
    filename: 'bundle.js'
  }
}

page.html

<html>
  <head>
    ...
  </head>
  <body>
    ...
    <script src="bundle.js"></script>
  </body>
</html>

然后在命令行运行 webpack 就会创建 bundle.js.