Run results for: Object.fromEntries vs new Map vs Reduce

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:139.0) Gecko/20100101 Firefox/139.0

Browser: Firefox 139

Operating system: Windows

Device Platform: Desktop

Date tested: 11 months ago

Test name	Executions per second
Object.fromEntries with Array.map	3651.4 Ops/sec
new Map with Array.map	1373.0 Ops/sec
Reduce (reusing object)	7057.3 Ops/sec
Reduce (creating temporary objects)	0.3 Ops/sec

Script Preparation code:

var ids = Array.from(Array(10000).keys())

var data = ids.map(item => ({ id: item, random: Math.random() }))

Tests:

Object.fromEntries with Array.map
// Create the dictionary // Using `Object.fromEntries` and `Array.map` const dictionary = Object.fromEntries( data.map((item) => [ // Key item.id, // Item item, ]) ); // Utilize it, to test the performance of the dictionary itself as well. ids.map((id) => dictionary[id]);
new Map with Array.map
// Create the dictionary // Using `new Map` and `Array.map` const dictionary = new Map( data.map((item) => [ // Key item.id, // Item item, ]) ); // Utilize it, to test the performance of the dictionary itself as well. ids.map((id) => dictionary.get(id));
Reduce (reusing object)
// Create the dictionary // Using `Array.reduce` // And reusing the object const dictionary = data.reduce((obj, item) => { obj[item.id] = item; return obj; }, {}); // Utilize it, to test the performance of the dictionary itself as well. ids.map((id) => dictionary[id]);
Reduce (creating temporary objects)
// Create the dictionary // Using `Array.reduce` // And NOT reusing the object const dictionary = data.reduce((obj, item) => { return { ...obj, [item.id]: item }; }, {}); // Utilize it, to test the performance of the dictionary itself as well. ids.map((id) => dictionary[id]);