Run results for: Access Object, Map, Set

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:99.0) Gecko/20100101 Firefox/99.0

Browser: Firefox 99

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Get from Object	58647.7 Ops/sec
Has key in Object	60024.8 Ops/sec
Get from Map	47723.5 Ops/sec
Has key in Map	49501.6 Ops/sec
Has key in Set	49234.9 Ops/sec

Script Preparation code:

var keys = [];
var prefix = 'someKeyPrefix';
var obj = {};
var map = new Map();
var set = new Set();

for (var i = 0; i < 300; i++) {
    var key = prefix + i;
    keys.push(key);
    if (i % 3) {
        obj[key] = true;
        map.set(key, true);
        set.add(key);
    }
}

Tests:

Get from Object
for (const key of keys) { var val = obj[key] }
Has key in Object
for (const key of keys) { var has = key in obj }
Get from Map
for (const key of keys) { var val = map.get(key) }
Has key in Map
for (const key of keys) { var has = map.has(key); }
Has key in Set
for (const key of keys) { var has = set.has(key); }

Run results for: Access Object, Map, Set

Get from Object

Has key in Object

Get from Map

Has key in Map

Has key in Set