Aliaksandr Kalenik 81b6a1100e LibJS: Skip iterator result object allocation in for..of and for..in ...

Introduce special instruction for `for..of` and `for..in` loop that
skips `{ value, done }` result object allocation if iterator is builtin
(array, map, set, string). This reduces GC pressure significantly and
avoids extracting the `value` and `done` properties.

This change makes this micro benchmark 48% faster on my computer:
```js
const arr = new Array(10_000_000);
let counter = 0;
for (let _ of arr) {
    counter++;
}
```

2025-04-30 20:51:39 +02:00

168 KiB

Raw Blame History

View Raw