Run results for: map-values

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser: Chrome 112

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Reduce + spread	0.4 Ops/sec
Loop (for...in) with .keys()	73.7 Ops/sec
Loop (for...in) with .entries()	87.6 Ops/sec
Reduce + mutate	41.6 Ops/sec
Reduce + mutate with entries()	46.5 Ops/sec
Map with fromEntries	59.9 Ops/sec
Loop (for...in) with mutate	118.1 Ops/sec
Loop (for...in) with mutate (no guard)	116.4 Ops/sec

Script Preparation code:

fn = (val, key) => val.toString()
obj = Object.fromEntries([...Array(10000)].map((v, i) => ([i+1, i+1])))

Tests:

Reduce + spread
const keys = Object.keys(obj); return keys.reduce((carry, key) => ({ ...carry, [key]: fn(obj[key], key) }), {});
Loop (for...in) with .keys()
const keys = Object.keys(obj); let result = {}; for (let key of keys) { result[key] = fn(obj[key], key); } return result;
Loop (for...in) with .entries()
const entries = Object.entries(obj); let result = {}; for (let [key, value] of entries) { result[key] = fn(value, key); } return result;
Reduce + mutate
const keys = Object.keys(obj); return keys.reduce((carry, key) => (carry[key] = fn(obj[key], key)), {});
Reduce + mutate with entries()
const entries = Object.entries(obj); return entries.reduce((carry, [key, value]) => (carry[key] = fn(value, key)), {});
Map with fromEntries
Object.fromEntries( Object.entries(obj).map(([key, value]) => [key, fn(value, key)]) )
Loop (for...in) with mutate
const result = { ...obj }; for (const key in result) { if (result[key]) { result[key] = fn(result[key], key); } }
Loop (for...in) with mutate (Object.assign)
const result = Object.assign({}, obj); for (const key in result) { if (result[key]) { result[key] = fn(result[key], key); } }
Loop (for...in) with mutate (save object[key])
const result = { ...obj }; for (const key in result) { const value = result[key] if (result[key]) { result[key] = fn(result[key], key); } }
Loop (for...in) with unsafe mutate
for (const key in obj) { if (obj[key]) { obj[key] = fn(obj[key], key); } }
Object.fromEntries with map
Object.fromEntries(Object.entries(obj).map(([key, value]) => { return [key, fn(value, key)]; }));

Run results for: map-values

Reduce + spread

Loop (for...in) with .keys()

Loop (for...in) with .entries()

Reduce + mutate

Reduce + mutate with entries()

Map with fromEntries

Loop (for...in) with mutate

Loop (for...in) with mutate (Object.assign)

Loop (for...in) with mutate (save object[key])

Loop (for...in) with unsafe mutate

Object.fromEntries with map