The comment needs to be inside the root element to be preserved.

<template>
  <div class="hello">
    <!--hello-->  
    <h1>{{ msg }}</h1>
  </div>
</template>

Thank you，no effect. @yyx990803

Ah, we forgot to mention in the docs: the comments option only works when using the full build with in-browser compilation. It does not work in single file components.

vuejs/vue-loader#897

I have a comments in my index.html for a noscripttag before <div id="app"></div>, the comment shows fine on localhost but not on prod, any suggestion?

I've tried comments: true, in main.js with no luck