Javascript pointer/reference craziness. Can someone explain this?

Question

Javascript passes objects by reference. This makes perfect sense. But once you start manipulating those objects, everything acts in a way that seem unintuitive. Let me offer

Answer 1

:P You're descending into the knitty gritty details and I'm glad you asked, as you will be wiser by the end.

Don't look at it in terms of pointers, because I think that is where you are getting confused. Think of it rather in terms of the heap (or just "memory" if you will) and the symbol table.

Lets start by taking the first few lines of your code:

var a, b;

a = {}
b = a;

What you've done here is created one object on the heap and two symbols on the symbol table. It looks something like this:

---

Symbol Table:

+--------+-----------------+
| Symbol | Memory Location |
+--------+-----------------+
|      a |        0x400000 |
+--------+-----------------+
|      b |        0x400000 |
+--------+-----------------+

Heap:

+----------+-----------------+
| Location | Value           |
+----------+-----------------+
| 0x400000 |