Run results for: Reducer with object spread vs direct mutation

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser: Chrome 79

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
With object spread	2189308.0 Ops/sec
With parameter mutation	16710310.0 Ops/sec

Tests:

With object spread
const toReduce = [{key: 'a', value: 1}, {key: 'b', value: 2}, {key: 'c', value: 3}]; const reduced = toReduce.reduce((acc, cur) => { return { ...acc, [cur.key]: cur.value, }; }, {});
With parameter mutation
const toReduce = [{key: 'a', value: 1}, {key: 'b', value: 2}, {key: 'c', value: 3}]; const reduced = toReduce.reduce((acc, cur) => { acc[cur.key] = cur.value; return acc; }, {});