Clone a new object simply by assigning object to a variable using Immutable.js

Question

I'm looking at the documentation for Immutable.js, specifically the following:

var map1 = Immutable.Map({a:1, b:2, c:3});
var clone = map1;

but I'm confused as to how simply assigning map1 to clone creates a clone rather than a reference?

Update: The docs state "If an object is immutable, it can be "copied" simply by making another reference to it instead of copying the entire object. Because a reference is much smaller than the object itself, this results in memory savings and a potential boost in execution speed for programs which rely on copies (such as an undo-stack)."

I just tested this in a jsbin though, and clone does === map1. I think their use of the word 'clone' in the docs is a little misleading.

Answer 1

Since Immutable.Map is immutable, the notion of cloning is obsolete. Their point is that you don't have to bother about cloning or not, it doesn't matter.

The docs are indeed confusing, and indeed it is a reference not a clone. The effect of cloning would be the same anyways.