How to get my anonymous function to return a value instead of a function?

Question

My code:

var host_choice = function(){
    var choice;
    do {
        choice = shuffled_list[random_choice()];
    } while (choice == "car" || choice == player_choice);

    return choice;  
};

Here host_choice is a function which I would have to call. But I am unsure how to make it a variable containing choice. I know I am missing something basic here, but how to do it?

Side note: my shuffled_list contains 3 elements. And I want my host_choice variable to contain neither the element car nor the player_choice is there a "fancier" way of doing this?

Looks like an [IIFE](http://stackoverflow.com/questions/8228281/what-is-the-function-construct-in-javascript) would make the trick — taguenizy, Mar 28 '17 at 10:33

score 2 · Accepted Answer · answered Mar 28 '17 at 10:31

You can invoke it directly.

var host_choice = (function(){
  var choice;
  do {
      choice = shuffled_list[random_choice()];
  } while (choice == "car" || choice == player_choice);

  return choice;  
})();

This is an example of IIFE (Immediately Invoked Function Expression). It is very handy for various reasons, such as modularity in Javascript.

score 1 · Answer 2 · edited May 23 '17 at 10:30

You'd call it, with () after it:

var host_choice = function(){
    var choice;
    do {
        choice = shuffled_list[random_choice()];
    } while (choice == "car" || choice == player_choice);

    return choice;  
}(); // <====

Note that that means it will only ever be run once, since you don't keep a reference to the function anywhere.

You'll frequently see this written with () around the function part, too:

var host_choice = (function(){
    var choice;
    do {
        choice = shuffled_list[random_choice()];
    } while (choice == "car" || choice == player_choice);

    return choice;  
})(); // <====

In your case, that's completely a matter of style, you don't need them. If you weren't using the return value, though, you'd need them so the parser didn't think the function keyword was starting a function declaration. (Which is where style comes in: Some people prefer to always include them even when they aren't strictly necessary, since they're necessary sometimes.) Details on that bit in my answer here.

How to get my anonymous function to return a value instead of a function?

2 Answers2