Benchmark: JavaScript fastest way to clone an object including JSON.parse and structuredClone methods

Tests:

Using the spread operator
const firstObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 }; const finalObject = {...firstObject};
Using Object.assign
const firstObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 }; const finalObject = Object.assign({}, firstObject);
Manually copying properties
const firstObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 }; let finalObject = {}; finalObject.prop0 = firstObject.prop0; finalObject.prop1 = firstObject.prop1; finalObject.prop2 = firstObject.prop2; finalObject.prop3 = firstObject.prop3; finalObject.prop4 = firstObject.prop4; finalObject.prop5 = firstObject.prop5;
Create new object while copying
const firstObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 }; const finalObject = { prop0: firstObject.prop0, prop1: firstObject.prop1, prop2: firstObject.prop2, prop3: firstObject.prop3, prop4: firstObject.prop4, prop5: firstObject.prop5 };
Create new object from scratch
const firstObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 }; const finalObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 };
StructuredClone
const firstObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 }; const finalObject = structuredClone(firstObject);
JSON
const firstObject = { prop0: 'Hello world', prop1: 1, prop2: 2, prop3: "3", prop4: false, prop5: 0.2 }; const finalObject = JSON.parse(JSON.stringify(firstObject));

Historical Performance Data aggregated from 12 community runs

Desktop Results:

Chrome 12 runs

Create new object from scratch

162.9M/s

Create new object while copying

159.1M/s

Manually copying properties

146.9M/s

Using the spread operator

49.0M/s

Using Object.assign

12.9M/s

JSON

3.1M/s

StructuredClone

808K/s

Fastest: Create new object from scratch (201.6x faster)

View exact numbers

✓ Create new object from scratch: 162,857,216 ops/sec
• Create new object while copying: 159,094,688 ops/sec
• Manually copying properties: 146,901,056 ops/sec
• Using the spread operator: 49,019,032 ops/sec
• Using Object.assign: 12,917,174 ops/sec
• JSON: 3,130,641 ops/sec
• StructuredClone: 807,705 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
Using the spread operator
Using Object.assign
Manually copying properties
Create new object while copying
Create new object from scratch
StructuredClone
JSON

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Mobile Safari/537.36 OPR/95.0.0.0

Browser/OS: Opera Mobile 95 on Android

View result in a separate tab

Create new object from scratch

127.2M/s

Manually copying properties

119.9M/s

Create new object while copying

119.5M/s

Using the spread operator

40.5M/s

Using Object.assign

10.6M/s

JSON

2.2M/s

StructuredClone

332K/s

View exact numbers

Test name	Executions per second
✓ Create new object from scratch	127,190,776 Ops/sec
Manually copying properties	119,866,712 Ops/sec
Create new object while copying	119,516,416 Ops/sec
Using the spread operator	40,543,332 Ops/sec
Using Object.assign	10,563,756 Ops/sec
JSON	2,229,924 Ops/sec
StructuredClone	331,637 Ops/sec

JavaScript fastest way to clone an object including JSON.parse and structuredClone methods (version: 1)

Comparing performance of: `Using the spread operator vs Using Object.assign vs Manually copying properties vs Create new object while copying vs Create new object from scratch vs StructuredClone vs JSON`

Created: one year ago by: Guest

Go to the latest result

Using the spread operator

Using Object.assign

Manually copying properties

Create new object while copying

Create new object from scratch

StructuredClone

JSON

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

JavaScript fastest way to clone an object including JSON.parse and structuredClone methods (version: 1)

Comparing performance of: Using the spread operator vs Using Object.assign vs Manually copying properties vs Create new object while copying vs Create new object from scratch vs StructuredClone vs JSON

Created: one year ago by: Guest

Go to the latest result

Using the spread operator

Using Object.assign

Manually copying properties

Create new object while copying

Create new object from scratch

StructuredClone

JSON

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: `Using the spread operator vs Using Object.assign vs Manually copying properties vs Create new object while copying vs Create new object from scratch vs StructuredClone vs JSON`