Run results for: Sparse array vs Map for random access and iteration

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 138

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

Iterate array

1.7M/s

Iterate map

1.2M/s

Get from map (with misses)

770K/s

Get from array (all hits)

710K/s

Get from map (all hits)

34K/s

Get from array (with misses)

404/s

View exact numbers

Test name	Executions per second
✓ Iterate array	1,720,928 Ops/sec
Iterate map	1,165,826 Ops/sec
Get from map (with misses)	769,763 Ops/sec
Get from array (all hits)	710,399 Ops/sec
Get from map (all hits)	34,146 Ops/sec
Get from array (with misses)	404 Ops/sec

Script Preparation code:

window.indexes = [];
window.arr = [];
window.map = new Map();
for (let i = 0; i < 1000; i++) {
	if (Math.random() > 0.7) {
		window.indexes.push(i);
		window.arr[i] = true;
		window.map.set(i, true);
	}
}

Tests:

Get from array (all hits)
for (const idx of window.indexes) { const a = window.arr[idx]; }
Get from array (with misses)
for (let i = 0; i < 1000; i++) { const a = window.arr[i]; }
Get from map (all hits)
for (const idx of window.indexes) { const a = window.map.get(idx); }
Get from map (with misses)
for (let i = 0; i < 1000; i++) { const a = window.map.get(i); }
Iterate array
for (const val of window.arr) { const a = val; }
Iterate map
for (const val of window.map) { const a = val; }