Benchmark: Object.assign vs spread operator vs structured clone vs for loop copy vs JSON duplicate with fallbacks

Object.assign vs spread operator vs structured clone vs for loop copy vs JSON duplicate with fallbacks (version: 7)

This test is only intended to be used to test for getting a new reference to an object, not generating a deep clone of an object. Some of the methods used here generate a deep copy and some a shallow copy, but the intent is only to find the fastest method of getting a shallow copy where the key length is long and there are lots of keys.

Comparing performance of: `Get copy using Object.assign vs Get copy using spread vs Get copy using structuredClone vs Copy manually using for loop vs Copy using JSON.stringify`

Created: one year ago by: Registered User

Go to the latest result

Script Preparation code:

const original = {
  'this is a somewhat long key with many characters0': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters1': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters2': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters3': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters4': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters5': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters6': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters7': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters8': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters9': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters10': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters11': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters12': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters13': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters14': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters15': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters16': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters17': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters18': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters19': 'This is a value of somewhat the same length',
  'this is a somewhat long key with many characters20': 'This is a value of somewhat the same length',
};

Tests:

Get copy using Object.assign
const newVersion = Object.assign({}, original ?? {});
Get copy using spread
const newVersion = { ...(original ?? {}) };
Get copy using structuredClone
const newVersion = structuredClone(original ?? {});
Copy manually using for loop
const newVersion = {}; const keys = Object.keys(original ?? {}); const len = keys.length; for (let i = 0; i < len; i++) { newVersion[keys[i]] = original[keys[i]]; }
Copy using JSON.stringify
const newVersion = JSON.parse(JSON.stringify(original ?? {}));

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Get copy using spread

8.7M/s

Copy manually using for loop

379K/s

Get copy using structuredClone

199K/s

Copy using JSON.stringify

174K/s

Fastest: Get copy using spread (50.4x faster)

View exact numbers

✓ Get copy using spread: 8,748,345 ops/sec
• Copy manually using for loop: 378,626 ops/sec
• Get copy using structuredClone: 198,837 ops/sec
• Copy using JSON.stringify: 173,748 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
Get copy using Object.assign
Get copy using spread
Get copy using structuredClone
Copy manually using for loop
Copy using JSON.stringify

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36 Edg/130.0.0.0

Browser/OS: Chrome 130 on Windows

View result in a separate tab

Get copy using spread

9.7M/s

Get copy using Object.assign

1.1M/s

Copy manually using for loop

484K/s

Copy using JSON.stringify

176K/s

Get copy using structuredClone

161K/s

View exact numbers

Test name	Executions per second
✓ Get copy using spread	9,728,743 Ops/sec
Get copy using Object.assign	1,143,950 Ops/sec
Copy manually using for loop	484,450 Ops/sec
Copy using JSON.stringify	176,001 Ops/sec
Get copy using structuredClone	160,712 Ops/sec

Object.assign vs spread operator vs structured clone vs for loop copy vs JSON duplicate with fallbacks (version: 7)

Comparing performance of: Get copy using Object.assign vs Get copy using spread vs Get copy using structuredClone vs Copy manually using for loop vs Copy using JSON.stringify

Created: one year ago by: Registered User

Go to the latest result

Get copy using Object.assign

Get copy using spread

Get copy using structuredClone

Copy manually using for loop

Copy using JSON.stringify

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `Get copy using Object.assign vs Get copy using spread vs Get copy using structuredClone vs Copy manually using for loop vs Copy using JSON.stringify`