Run results for: Map lookup vs array index lookup

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:123.0) Gecko/20100101 Firefox/123.0

Browser: Firefox 123

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Array lookup

15K/s

Map lookup

248/s

View exact numbers

Test name	Executions per second
✓ Array lookup	15,445 Ops/sec
Map lookup	248 Ops/sec

Script Preparation code:


var map = new Map();
var arrLookup = [];
var items = [];

for (var i = 0; i < 100; i++) {
  	items[i] = [];
	for (var j = 0; j < 100; j++) {
      	items[i][j] = [i,j];
		if (Math.random() < 0.1) {
        	map.set(i+","+j, Math.random()>=0.5);
          	if (!arrLookup[i]) arrLookup[i] = [];
          	arrLookup[i][j] = Math.random()>=0.5;
		}
	}
}

Tests:

Map lookup
var results = [], i, j; for (i = 0; i < 100; i++) { for (j = 0; j < 100; j++) { if (map.has(items[i][j] +"")) results.push(map.get(items[i][j]+"")); } } if (results.length === 0) throw Error();
Array lookup
var results = [], i, j; for (i = 0; i < 100; i++) { for (j = 0; j < 100; j++) { if (arrLookup[i] && typeof arrLookup[i][j] !== "undefined") results.push(arrLookup[i][j]); } } if (results.length === 0) throw Error();