How to write comments in ReactJS?

The comments in ReactJS/JSX is similar to javascript multiline comments which are wrapped with curly braces:

Single-line comments:

<div>
  {/* Single-line comments */}
  Welcome {user}, Let's play React
</div>

Multi-line comments:

<div>
  {/* Multi-line comments for more than
   one line */}
  Welcome {user}, Let's play React
</div>