Mastering JavaScript Functional Programming

Transformations

The first set of operations we are going to consider, work on an array, and process it in the base of a function to produce some results. There are several possible results: a single value, with the .reduce() operations; a new array, with .map(); or just about any kind of result, with .forEach().

If you Google around, you will find some articles that declare that these functions are not efficient, because a loop done by hand can be faster. This, while possibly true, is practically irrelevant. Unless your code really suffers from speed problems, and you are able to measure that the slowness derives from the usage of these higher-order functions, trying to avoid them, with longer code, and more probability of bugs simply doesn't ...