Is the order guaranteed when iterating an array with keys?

Asked May 17 '20 at 13:30

Active May 17 '20 at 13:30

Viewed 18 times

My code:

const data = {};
data["a"] = 1;
data["c"] = 2;
data["b"] = 3;

for (const id in data) {
    console.log(data[id]);
}

Result:

1
2
3

Is the result guaranteed to always be the same?

asked May 17 '20 at 13:30

Zack Lee

no, the order is not guaranteed – Mister Jojo May 17 '20 at 13:30
1

In modern environments, yes, [for all methods](https://stackoverflow.com/a/58444013) that iterate over keys. @MisterJojo Yes it is - it's an ES2020 thing, see the link – CertainPerformance May 17 '20 at 13:30
I suppose you look for a 100% guarantee, in any environment, no ? – Mister Jojo May 17 '20 at 13:33
In a single word, NO – Abhijit Srivastava May 17 '20 at 13:56
@AbhijitSrivastava See my link - it *is* guaranteed by the specification, and all environments have been doing so for many years anyway – CertainPerformance May 17 '20 at 14:36

0 Answers0