MeasureThat.net

Run results for: Map vs Object - string keys - read performance

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Run details:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.107 Safari/537.36
Chrome 92
Mac OS X 10.15.7
Desktop
3 years ago
Test name Executions per second
Read from map 1749678.5 Ops/sec
Read from obj 1403757.0 Ops/sec
Script Preparation code:
​x
 
window.myMap = new Map();
window.myObj = new Map();
window.generateObj = () => ({
    'a': Math.random() * 10000,
    'b': Math.random() * 10000,
    'c': Math.random() * 10000
});
​
for (let i = 0; i < 1000; i++) {
    let id = 'id-' + i;
    let obj = generateObj();
    myMap.set(id, obj);
    myObj[id] = obj;
}
Tests:

  • Read from map

     
    let id = `id-` + Math.floor(Math.random() * 1000);
    let value = myMap.get(id);

  • Read from obj

     
    let id = `id-` + Math.floor(Math.random() * 1000);
    let value = myObj[id];