Do Javascript variable assignments work by reference?

Question

I have a question about referencing objects in javascript.

Say I have a variable that is some object (lets say json) and it is called objOne - (var objOne = someJSONObject;).

If I go ahead and declare

var objTwo = objOne;

will I have two references to the same Object? Kind of like a c pointer?

Answer 1

To sum it up :

• assignements are done by value
• you never manipulate objects, only object references

This means that

• you'll have two references to the same object (you can check that by changing a property of the object)
• when you're passed in a variable the value of a primitive, changing your variable doesn't change other variables

EDIT : as it's a duplicate I'll delete this answer in a minute to allow a proper closing if there's no other answer. Please vote to close.

Answer 2

Yes, objects are passed by reference:

function changeVal(obj){
    obj.value = "bar"
}

(function checkRefs(){

    var myObject = {
        value: "foo"
    };


    alert(myObject.value);

    changeVal(myObject);

    alert(myObject.value);


})();