Arrays are in every web developer’s toolbox, and there are a dozen ways to iterate over them. Choose wrong, though, and all of that processing time will happen synchronously in one long, blocking task. The thing is, the most natural ways are the wrong ways. A simple for..of loop that processes each array item is synchronous by default, while Array methods like forEach and map can ONLY run synchronously. You almost certainly have a loop like this waiting to be optimized right now.
