React/JSX attrs w/strings vs braces

Question

The docs say that a JSX attributes with strings are the same as attributes with braces...

<Thing attr='val' /> === <Thing attr={'val'} />

I thought I read something that said only use braces when needed because strings are more performant, but I can't find the reference now. Is there an evaluation cost for braces?

Answer 1

No there is no performance difference. Look at the code that's generated by each style:

<div first="abc" second={"def"}/>

// Compiles to:
React.createElement("div", { first: "abc", second: "def" });

Nicer to avoid unneeded braces though.