Run results for: Mutate array vs memory efficient map

In memory constrained devices the use of .map() is not always possible. In such places, this should determine whether a mutation is better than creating a new array from scratch while emptying the original array, thus, keeping somewhat the same memory usage.

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_1_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.1.1 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 17

Operating system: iOS 17.1.1

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
Mutate array	99.7 Ops/sec
Memory efficient map	10872145.0 Ops/sec

Script Preparation code:

var test = [];

for (let i = 0; i < 100000; i++) {
  test.push(i);
}

Tests:

Mutate array
for (let i = 0; i < test.length; i++) { test[i] = i * 2; }
Memory efficient map
const copyTest = []; for (let i = 0; i < test.length; i++) { const currentItem = test.shift(); copyTest.push(currentItem * 2); }

Run results for: Mutate array vs memory efficient map

In memory constrained devices the use of .map() is not always possible. In such places, this should determine whether a mutation is better than creating a new array from scratch while emptying the original array, thus, keeping somewhat the same memory usage.

Mutate array

Memory efficient map