Foreach as a function is completely pointless though imo. reduce can all be useful for sure, I find myself using them frequently enough. Languages have keywords for looping for a reason, because they are core concepts that all programming is based on, your IDE will syntax highlight it and everything. forEach is more readable than an actual loop. Sure, everyone should know how to use all the original loops in javascript and use them well, but using a for loop versus map or even forEach (if you just have to mutate that existing array) is going the wrong I will never understand how people can say that. Regardless, I hate to say that I think you're giving bad advice here. Although I say 'sorta' as obviously you're going to need functions with side effects to make API calls, or logs, or write i/o (any function that has I/O). My point is that javascript gives us first class functions and in combination with it's (sorta) functional paradigms can produce: more readable code, better tooling, composition and patterns like higher order functions and currying, beautiful immutability, and many other wins such as referential transparency with pure functions - which reduce side effects and can increase run time, especially if memoized etc. Currently, the best use case would be for something like iterating an async generator function using the new for-await-of syntax. There are fewer and fewer cases where a for loop is viable. map() returns a new array, is much faster, and without the side effect of mutating the original array. Using for loops is like going backwards, not to mention that forEach is slow because it is modifying/mutating the original array, whereas. Beyond that, anyone who is worried about performance at this level can go back after they've built their app and measure the app's performance and decide where to optimize (and I will bet you will find most of your optimizations will not be refactoring map, filter, or reduce).

Functional programming is all about focusing not on how to solve problems and instead, shifts your focus to what to solve. These make use of functional paradigms, and these paradigms exist for a reason. but your overlooking the entire point of map, forEach, filter, reduce, find, findIndex, etc. Using for loops is easy enough sure, in most cases.

I completely disagree with this & please allow to explain why:

Javascript for each element in array