Run results for: spread vs mutation vs Object.assign for reduce callback

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.96 YaBrowser/20.4.0.3443 Yowser/2.5 Safari/537.36

Browser: Yandex Browser 20

Operating system: Mac OS X 10.15.4

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
with spread operator	760239.3 Ops/sec
with mutation	3069460.0 Ops/sec
with object assign	131852.8 Ops/sec

Tests:

with spread operator
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { return { ...acc, [num]: num } }, {})
with mutation
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { acc[num] = num return acc }, {})
with object assign
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { return Object.assign(acc, {[num]: num}) }, {})

Run results for: spread vs mutation vs Object.assign for reduce callback

with spread operator

with mutation

with object assign