Run results for: Convert Array to Object - Compare all possible4

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser: Chrome 121

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

forEach

19K/s

for of

18K/s

Reduce (reuse object)

18K/s

Object.fromEntries

3K/s

for i saved length variable

3K/s

Map

2K/s

for i

1K/s

Reduce (creating temporary objects)

121/s

View exact numbers

Test name	Executions per second
✓ forEach	18,835 Ops/sec
for of	18,485 Ops/sec
Reduce (reuse object)	18,108 Ops/sec
Object.fromEntries	2,716 Ops/sec
for i saved length variable	2,625 Ops/sec
Map	2,078 Ops/sec
for i	1,461 Ops/sec
Reduce (creating temporary objects)	121 Ops/sec

Script Preparation code:

var data = Array.from(Array(10000).keys()).map(i => ({id: i, value: `val_${i}`}));

Tests:

Object.fromEntries
Object.fromEntries(data.map(obj => [obj.id, obj]));
Reduce (reuse object)
data.reduce((acc, obj) => { acc[obj.id] = obj; return acc; }, {});
Reduce (creating temporary objects)
data.reduce((acc, obj) => ({ ...acc, [obj.id]: obj }), {});
Map
new Map(data.map(obj => [obj.id, obj]));
forEach
const res = {}; data.forEach(obj => { res[obj.id] = obj; });
for of
const res = {}; for (const obj of data) { res[obj.id] = obj; }
for i
const res = {}; for (let i = 0; i < data.length; i++) { const obj = data[i]; res[obj.id] = obj; }
for i saved length variable
const res = {}; const length = data.length; for (let i = 0; i < length; i++) { const obj = data[i]; res[obj.id] = obj; }