Question

I have an object that looks like this:

var MyObject = {
prop1 = 12345,
prop2 = "string1",
ListOfOtherObject = an array of another type of object,
ListOfAnotherObject = an array of objects}

Let’s say I have two objects: Object1 and Object2. Object2 was initially a deep-copy of Object1 and it was modified through the user’s interactions with the UI. I’m looking to get the difference between both objects, especially when it comes to the arrays.

For instance, ListOfOtherObject in Object2 might contain a modified version of some objects as well as new objects.

I’m thinking about looping through each array and then looping through each object within but there might be some more efficient way to do it, especially with jquery. Or may be going with JSON.stringify and compares strings and retuns some sort of string difference. I was wondering if anyone had any suggestions on how to do this.

Thanks.

Answer 1

You need to specify what your comparison needs to do. For example, given:

var o = {name: 'fred'};
var p = {name: 'fred'};
var a = {o:o};
var b = {o:o};

then:

a == b;     // false, a and b are different objects
a.o == b.o; // true since a.o and b.o reference the same object

but if comparing objects:

b.o = p;
a.o == b.o; // false since a.o and b.o reference different objects

or if comparing primitives:

a.o.name == b.o.name; // true since the value of both expressions is the string 'fred'
                      // even though a.o and b.o are different objects

Does Type or constructor matter? What about:

b.o = [];
b.o.name = 'fred';

a.o.name == b.o.name;  // true or false? a.o is an object, b.o is an array