Exercise - Objects

by jordwms

JavaScript

// 1)
//
// Create a function that accepts an object as an argument
// and returns a copy of that object
// So that the following example will run correctly

// 2)
//
// Make sure the function ONLY copies "own" properties
// hint: use hasOwnProperty()
var joe = {
    name: "Joe",
    age: 32
}

function copy(obj) {
    var newObj = new Object(), 
        keys   = Object.getOwnPropertyNames(obj);
    
    /* Insert your functionality here */
 	// loop through the object, property is the 'name'
    keys.forEach(function(property) { 
    	Object.defineProperty(
            newObj, 
            property, 
            Object.getOwnPropertyDescriptor(obj, property)
        );
    });
    
    return newObj;
}

// Testing your copy function...
var jim = copy(joe);
console.group("Test");
if (jim === joe) {
    console.log("Nope! They are the same object")   
} else {
     console.log("Great job! You made a copy.");   
}
console.log("The two objects are:", jim, ",", joe);
console.groupEnd();

// 3) Bonus
//
// Add the function as a method on the joe object, 
// then invoke the method of that object to copy it
// hint: you will use "this" keyword in your method
//
// ex: joe.copy(); // outputs a copy
console.group('#3 Bonus');
joe.copy = function() {
    var newObj = new Object(), 
        keys   = Object.getOwnPropertyNames(this),
        that   = this;
    
    /* Insert your functionality here */
 	// loop through the object, property is the 'name'
    keys.forEach(function(property) { 
       	Object.defineProperty(
            newObj, 
            property, 
            Object.getOwnPropertyDescriptor(that, property)
        );
    });
    
    return newObj;
}

console.log( joe.copy() );
console.groupEnd();