ReactDOM.render()'s first argument should evaluate to a JSX expression, it doesn't have to literally be a JSX expression.
The first argument could also be a variable, so long as that variable evaluates to a JSX expression.
In this example, we save a JSX expression as a variable named
toDoList. We then pass
toDoList as the first argument to
var toDoList = (
<li>Become a Developer</li>