Run results for: Object spreading vs mutation in reduce

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36

Browser: Chrome 76

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Object spreading	1602.2 Ops/sec
Mutation	45860.1 Ops/sec

Tests:

Object spreading
[...new Array(1000)].reduce( (acc, item, index) => ({ ...acc, [index]: {} }), {}, );
Mutation
[...new Array(1000)].reduce( (acc, item, index) => { acc[index] = {}; return acc; }, {}, );