To the extent this tool will make it appear that there is less usage of functional JS patterns browser vendors deciding how to optimize their engines, I'm not a

To the extent this tool will make it appear that there is less usage of functional JS patterns browser vendors deciding how to optimize their engines, I'm not a fan. Compiling away a useful feature or pattern just because it's not yet optimized creates a risk of a self-fulfilling prophecy. Obviously this is not a zero-sum game and optimizing for one pattern doesn't necessarily mean that something else must suffer, but prioritization of what to optimize is sometimes based on instrumentation measuring deployed usage and not just artificial benchmarks. The performance gap between a `for` loop and and a `.forEach` (also map) is much narrower than it used to be, and that is very encouraging.