Run results for: Array spread operator vs push in reduce 2

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.117 Safari/537.36

Browser: Chrome 79

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
spread operator	95903.0 Ops/sec
Push	111686.6 Ops/sec

Tests:

spread operator
var arr = [ { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, ] arr.reduce((acc, findingInOpp) => [...acc, ...findingInOpp.findingList.map(({ findingId }) => findingId)],[])
Push
var arr = [ { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, { "opportunityId": 5943111, "findingList": [ {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, {"findingId": 6919 }, ], }, ] arr.reduce((acc, findingInOpp) => { acc.push(...findingInOpp.findingList.map(({ findingId }) => findingId)) return acc },[])

Run results for: Array spread operator vs push in reduce 2

Compare the new ES6 spread operator with push inside reduce

spread operator

Push