Benchmark: array.map() with spread vs for-loop

Script Preparation code:

var entries = Object.entries({ ...Array.from(Array(10000).keys()) });

Tests:

Object.fromEntries with spread
const obj = Object.fromEntries([ ...entries.map((key, value) => [key, value]) ]);
for-loop and object (reuse object)
const obj = {}; for (const [key, value] of entries) { obj[key] = value; }
for-loop and object (creating temporary objects)
let obj = {}; for (const [key, value] of entries) { obj = { ...obj, [key]: value }; }
for-loop and map
const map = new Map(); for (const [key, value] of entries) { map.set(key, value); } const obj = Object.fromEntries(map);

Rendered benchmark preparation results:

Previous results

Test case name	Result
Object.fromEntries with spread
for-loop and object (reuse object)
for-loop and object (creating temporary objects)
for-loop and map

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser/OS: Chrome 122 on Mac OS X 10.15.7

for-loop and object (reuse object)

8K/s

for-loop and map

849/s

Object.fromEntries with spread

154/s

for-loop and object (creating temporary objects)

54/s

View exact numbers

Test name	Executions per second
✓ for-loop and object (reuse object)	7,520 Ops/sec
for-loop and map	849 Ops/sec
Object.fromEntries with spread	154 Ops/sec
for-loop and object (creating temporary objects)	54 Ops/sec

array.map() with spread vs for-loop (version: 0) Benchmark.js