Elements order in a “for (… in …)” loop

Question

Does the \"for…in\" loop in Javascript loop through the hashtables/elements in the order they are declared? Is there a browser which doesn\'t do it in order?
The object

Answer 1

As stated by other answers, no, the order is not guaranteed.

If you want to iterate in order, you can do something like:

let keys = Object.keys(myObject);
for (let key of keys.sort()) {
  let value = myObject[key];
  
  // Do what you want with key and value 
}

Note that performance-wise, this is not optimal, but that's the price when you want a nice alphabetical display.