JavaScript functions - first class objects

javascript_functions_first_class.js

/*
Functions are first class objects, which means you can:
- store them in a variable
- store them in an array
- pass them as an argument to a function
- return them from a function
*/

// store a function in a variable
var smart_play = function(num) {
    return num * 2;
};

console.log(smart_play);

// store a variable containing a function in an array
var my_stuff = ['indecision', 'grapes', smart_play, 42];

console.log(my_stuff);

// store another function in a variable
// this function accepts a function as its second parameter
// and returns a function
var gamble = function(num, gamble_function) {
    // powerful stuff going on here!
    var result = gamble_function(num);
    
    return function(name) {
        alert("Hello " + name + ". You started out with " + num + " and ended up with " + result + ".");
    };
};

// pass in the function by name
var my_gamble = gamble(10, smart_play);
my_gamble("Teddy KGB");

console.log(my_gamble);

// pass in the function from its array position
var my_gamble2 = gamble(15, my_stuff[2]);
my_gamble2("Mike McDermott");

console.log(my_gamble2);

// why are these different? they look the same, right?
console.log(my_gamble === my_gamble2);