Benchmark: map spread vs manual vs assign

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);

Historical Performance Data aggregated from 12 community runs

Desktop Results:

Chrome 12 runs

literal

21K/s

spread

7K/s

assign

2K/s

Fastest: literal (8.3x faster)

View exact numbers

✓ literal: 20,625 ops/sec
• spread: 6,903 ops/sec
• assign: 2,487 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
literal
assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 11 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Linux

View result in a separate tab

literal

18K/s

spread

9K/s

assign

3K/s

View exact numbers

Test name	Executions per second
✓ literal	18,431 Ops/sec
spread	8,700 Ops/sec
assign	2,942 Ops/sec

map spread vs manual vs assign (version: 1)

Comparing performance of: `spread vs literal vs assign`

Created: 11 months ago by: Guest

Go to the latest result

spread

literal

assign

Historical Performance Data aggregated from 12 community runs

Desktop Results:

Chrome 12 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

map spread vs manual vs assign (version: 1)

Comparing performance of: spread vs literal vs assign

Created: 11 months ago by: Guest

Go to the latest result

spread

literal

assign

Historical Performance Data aggregated from 12 community runs

Desktop Results:

Chrome 12 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `spread vs literal vs assign`