Part 1: call, apply and bind

Lately I have been doing some more coding again with NodeJS or maybe better to say Javascript :)

I will be adding some short items about things so that I dont forget and maybe also can help others with explaining what specific functions do.

Today we start with call , apply and bind. To explain the differences I have created some small code which should explain it all in a simple way:

var obj = { num:2 };

var functionName = function(arg1, arg2, arg3){
    return obj.num + arg1 + arg2 + arg3;
};

// call a object with an outside function
console.log('call: ' , functionName.call(obj, 1,2,3));

// call a object with an outside function, same but with an array as arguments
console.log('apply: ', functionName.apply(obj, [1,2,3]));

// call a new object with a merged function inside
var bound = functionName.bind(obj);
console.log('bound: ' , bound(1,2,3));

As you can see, call & apply are almost the same. bound clearly has a different use-case.