Run results for: map spread vs manual vs assign

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.5 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 18

Operating system: iOS 18.5

Device Platform: Mobile

Date tested: 11 months ago

literal

13K/s

spread

5K/s

assign

2K/s

View exact numbers

Test name	Executions per second
✓ literal	13,055 Ops/sec
spread	5,496 Ops/sec
assign	1,574 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

function mapObjectSpread(obj) {
    return {
        ...obj,
        id: obj.objId
    };
}

function mapObjectLiterally(obj) {
    return {
        objId: obj.objId,
        a: obj.a,
        b: obj.b,
        c: obj.c,
        id: obj.objId
    };
}

function mapObjectAssign(obj) {
    return Object.assign({}, obj, {
        id: obj.objId
    });
}

const objs = [];
for (let i = 0; i < 10000; i++) {
    objs.push({
        a: "a",
        b: "b",
        c: "c",
        objId: i
    });
}

Tests:

spread
objs.map(mapObjectSpread);
literal
objs.map(mapObjectLiterally);
assign
objs.map(mapObjectAssign);