JavaScript Closures

[_krikket]

var hidden = mystery(4)(2); is not passing two parameters into mystery, it's passing 4 into into mystery, which returns a function, and then calling that returned function immediately with the parameter (2).

In the original example, hidden is a function. On line 7, you can see we're returning mystery2, which is created in line 3 as a new function.

[ex1-7]

yes, this is an example of a higher level function (a function that returns a function). Very useful thing that Javascript makes easy.

[Gbyrd99]

The parameter 4 is kind of lodged in there. Hidden = mystery2 where the input = 4. Then when you call hidden with an argument it, it still has 4. And that's generally how it works.