title: what is the relationship of babel polyfill and runtime?
body: <blockquote>
    <p>Babel includes a polyfill that includes a custom regenerator runtime
    and core-js.</p>
    
    <p>Another purpose of this transformer is to create a sandboxed
    environment for your code. If you use babel-polyfill and the built-ins
    it provides such as Promise, Set and Map</p>
  </blockquote>
  
  <p>According to the documentation,I have think about these information and get the follow points:</p>
  
  <ol>
  <li>polyfill is included in babel,so if we use babel-loader,polyfill will be automatically contained in the transpiled result.</li>
  <li>babel-plugin-transform-runtime will only alias the name of the important classes,itself does not contain any polyfill or runtime.</li>
  <li>if you don't use babel-plugin-transform-runtime,the polifill will also be contained in the transpiled result,but without being aliased.</li>
  </ol>
  
  <p>Am I right?</p>