What's under the hood of [].forEach()?

Question

JavaScript

Dear Toasters. Please help me with info. Nowhere is this mechanism described normally.
It is very important to understand how forEach works on an array. Namely:
1. Why is it necessary to explicitly pass the context as the second parameter?
2. Where is the callback called from every time?
3. Is the callback a new object each time?
4. How does the method work step by step, in detail?
Please write down to the smallest detail.

Answer 1

1. If you don't want it, don't pass it on. It is not needed at all, you can use bind to pass this https://jsfiddle.net/eyc8cmqu/1/
2. I mean where? The callback is called in the same context where forEach
3 is called. It's the same function. . If you are talking about a passed argument, then it is the array element that is passed to the function as the first argument, if it is a primitive, then it is copied to the function by value.
4. Loops from 0 to the original length of the array and executes a callback on each existing element.
It's all written https://developer.mozilla.org/ru/docs/Web/JavaScri...
upd corrected the answer after criticism from the user Anton Spirin