Run results for: Spread vs FlatMap w/40K data

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser: Chrome 131

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Spread	415.2 Ops/sec
FlatMap	249.5 Ops/sec

Script Preparation code:

const arr = Array.from({
    length: 40000
}).map((_, index) => ({
    id: index,
    label: `lbl`,
    plate: `plt`
}));

Tests:

Spread
let x = [...arr?.map((item) => ({ ...item, label: item.label, value: item.id, })), ...arr?.map((item) => ({ ...item, label: item.plate, value: item.id, })),]
FlatMap
let y = arr?.flatMap((item) => [ { ...item, label: item.label, value: item.id }, { ...item, label: item.oldLicensePlate, value: item.id }, ])