A function that takes an argument and returns a function that returns that argument

Question

I am trying to wrap my brains around the fact that something equals the value of the returned anonymous function value. I thought with scoping it wouldn't have had access to the functions variables.

So how does calling something give you the value of 3?

 function somefun (x){
     return function(){
         return x;
     }
 }

 var something = somefun (3);
 something();
 //3

No, there is no scope issue here. I suggest reading a good article about javascript scope/closures. — Yoshi, Feb 22 '13 at 16:02
Well, i know that `x` doesn't know anything outside of `somefun` so how does `something` now have access to a variable inside of `sunfun` — Jamie Hutber, Feb 22 '13 at 16:04
@JamieHutber As I wrote, read a good article about the issue. You simply have a wrong conception of how/why this is working. — Yoshi, Feb 22 '13 at 16:05
see rockets answer :) I've read many a good books. Among them mr Douglas's good parts. — Jamie Hutber, Feb 22 '13 at 16:06
just like this http://stackoverflow.com/questions/7629891/functions-that-return-a-function-javascript — Pandian, Feb 22 '13 at 16:08

score 2 · Accepted Answer · answered Feb 22 '13 at 16:03

2

In JavaScript, functions are just objects, like anything else. Functions can be assigned to variables.

So somefun returns a function, which is assigned to something. Thus, something is a function.

So, when something() is ran, it returns a value, because it's a function.

That function is called a "closure". It keeps a reference to the x value, which is why it's returned to you.

answered Feb 22 '13 at 16:03

gen_Eric

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so it runs the function, cool. argh pants. Makes sense now, as you gave the function to a variable. ekk i knew this. I just had a brain fart! – Jamie Hutber Feb 22 '13 at 16:05

A function that takes an argument and returns a function that returns that argument

1 Answers1