Run results for: Reduce and Spread vs. Foreach and Mutate 3

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36

Browser: Chrome 127

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

ForEach and Mutate (for .. in loop)

237K/s

reduce mutate 2

232K/s

Mutate with Object.assign

159K/s

Reduce and Spread

56K/s

Reduce Mutate

15K/s

reduce mutate 3

14K/s

Foreach and Mutate (Object.assign)

14K/s

View exact numbers

Test name	Executions per second
✓ ForEach and Mutate (for .. in loop)	237,258 Ops/sec
reduce mutate 2	232,358 Ops/sec
Mutate with Object.assign	159,432 Ops/sec
Reduce and Spread	56,009 Ops/sec
Reduce Mutate	15,005 Ops/sec
reduce mutate 3	14,103 Ops/sec
Foreach and Mutate (Object.assign)	13,881 Ops/sec

Script Preparation code:

var objectsArray = Array(1000).fill(() => {
  const key = Math.random().toString(36).substring(2, 5);
  const value = Math.random().toString(36).substring(2, 5);
  return {[key]: value};
});

Tests:

Reduce and Spread
var combined = objectsArray.reduce((memo, obj) => ({...memo, ...obj}), {});
ForEach and Mutate (for .. in loop)
var combined = {} objectsArray.forEach(obj => { for (key in obj) { combined[key] = obj[key]; } });
Mutate with Object.assign
var combined = Object.assign(...objectsArray)
Foreach and Mutate (Object.assign)
var combined = {} objectsArray.forEach(obj => Object.assign(combined, obj));
Reduce Mutate
var combined = objectsArray.reduce((memo, obj) => Object.assign(memo, obj), {});
reduce mutate 2
var combined = objectsArray.reduce((acc, obj) => { for (key in obj) { acc[key] = obj[key]; } return acc; }, {});
reduce mutate 3
var combined = objectsArray.reduce((acc, obj) => { Object.keys(obj).forEach((key) => acc[key] = obj[key]); return acc; }, {});