And you can inline if-statements with an IIFE when you need a little more space:

    {(() => {
      if (cond1 && cond2)
        return <div>foo</div>
      else 
        ...
    })()}

Though it makes GitHub think it's a Clojure file.

     {(() => {
     })()}

Honestly I can't decide if I think this is ugly or beautiful. It's like the buffalo buffalo of JS.

That's something the "do expressions" ECMAScript proposal is meant to solve:

    {do {
      if (cond1 && cond2)
        <div>foo</div>
      else 
        ...
    }}

If JSX decides to implement "implicit" "do expressions", I suppose it would just look like this:

    {
      if (cond1 && cond2)
        <div>foo</div>
      else 
        ...
    }

http://wiki.ecmascript.org/doku.php?id=strawman:do_expressio...

It’s interesting to see that there are so many ways of doing conditions in JSX. I myself wrote a tiny library (http://github.com/yuanchuan/cond) for it several months ago and thought it made the code looks clean but suffers the same undefined issue though.