When do you use var and let to declare variables?

Could you walk through another example of functions returning functions? / Can you explain more on the Functions as Return Values please? Going through the logic a bit.

What is the purpose of an anonymous function / what are anonymous functions and how can they be used/when to use them? / More on anonymous functions.


Could you give more examples of anonymous and named function side by side?

Could you provide more clarification on sections of callback functions and functions as return values?

Could we explain arrow functions a bit more?

"A method similar to .map is forEach(), which takes a function of up to three arguments: the item, its index in the array, and the array itself. In practice, the third argument is often ignored, and we will omit it here. (Remember that JavaScript allows you to invoke a function with more arguments than it's declared to take. The extra arguments are just ignored. Here, if we supply an anonymous function that takes only two arguments, it means we aren't interested in the third argument — the array.)

In this part of the reading, you say that the third argument is ignored and omitted. Why so? "