Run results for: Copy vs traversal

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser: Chrome 112

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Spread and single traverse	2801470.8 Ops/sec
No spread and double traverse	1946386.9 Ops/sec

Script Preparation code:

globalThis.obj1 = Array.from({ length: 100000 }).reduce((p, c) => ({ ...p, [c]: c }), {})
globalThis.obj2 = Array.from({ length: 100000 }).reduce((p, c) => ({ ...p, [c]: c }), {})

Tests:

Spread and single traverse
Object.values({ ...obj1, ...obj2 }).every(e => e === undefined)
No spread and double traverse
Object.values(obj1).every(e => e === undefined) Object.values(obj2).every(e => e === undefined)

Run results for: Copy vs traversal

Spread and single traverse

No spread and double traverse