I would say the second one, because short-circuit evaluation is awesome; it helps you write concise, bloat-free code.

Short-cut what? 💁

I'll let Wikipedia do the talking:

Short-circuit evaluation, minimal evaluation, or McCarthy evaluation (after John McCarthy) is the semantics of some Boolean operators in some programming languages in which the second argument is executed or evaluated only if the first argument does not suffice to determine the value of the expression: when the first argument of the AND function evaluates to false, the overall value must be false; and when the first argument of the OR function evaluates to true, the overall value must be true.

This holds true even in JS:

• In the statement conditional && expression, expression isn't evaluated unless the conditional is true.
• In the statement conditional || expression, expression isn't evaluated unless the conditional is false.

do-expressions are also useful for this. There is a babel-plugin for this.

Nothing wrong with either way but React's docs even point to use the && operator for conditional 'if' rendering.

facebook.github.io/react/docs/conditional-renderi…

and it's less code!