How to iterate over an object in coffeescript?

Question

CoffeeScript

There is an object

moscow = 
    "cao": 4500
    "yua": 4500
    "yuvao": 4500
    "vao": 4500	
    "svao": 3800
    "sao": 3500
    "szao": 3800
    "zao": 4500
    "yuzao": 4500

You have to cycle through it.
Tried doing it like this

for key in moscow
    if key == currentRegion
      alert "Совпадение"

It compiles to this

results = [];
    for (i = 0, len = moscow.length; i < len; i++) {
      key = moscow[i];
      if (key === currentRegion) {
        results.push(alert("Совпадение"));
      } else {
        results.push(void 0);
      }
    }
    return results;

And shit doesn't work.
The debugger shows the following

That is, for some reason , len is undefined
Along the way, I'm doing something wrong. Maybe there are some more correct methods of how to do what I need for Coffee?

Answer 1

Thank you all very much, I figured it out myself.
In short, this is how it works

for key of moscow
    if key == currentRegion
      alert "Совпадение"

That is, we change the word in to of and immediately everything is nishtyak

Answer 2

Read about the length of js objects (you still need to know this). You will be as surprised as I was the first time.