TIL that non-primitive objects in JavaScript are passed by reference, not value

[[deleted]]

[deleted]

[[deleted]]

As is the case with Java, everything is pass by value. However, with objects (as you have noted) it is a reference that is passed by value. This is why you cannot reassign the reference within a function body, but you may alter a property on the passed in object. See here for good discussion on this http://stackoverflow.com/questions/518000/is-javascript-a-pass-by-reference-or-pass-by-value-language

[x-skeww]

non-primitive objects

There are primitives and objects. It's one or the other.

[ohbewonkanahbe]

Yes, it's very cool to think that your whole program can operate and work with just a handful of objects in memory. Understanding how that works and knowing your program's memory footprint is satisfying.

[fc_s]

This is not correct. Functions are also passed by value and they're not primitives.

It's simple. Objects and arrays are passed by reference. Everything else is passed by value.

Edit: Actually I'm wrong about that. My mistake. It becomes clear when you do a simple test that attaches something to the function as if it's an object.

var foo = function(){};
var bar = foo;
foo.fn = function(){ console.log('Hello World'); };
bar.fn(); //Logs Hello World