Benchmark: Deep copy comparison

Deep copy comparison (version: 0) Benchmark.js

Benchmarks for StackOverflow question on deep copy techniques https://stackoverflow.com/questions/7486085/copy-array-by-value/23536726#23536726

Comparing performance of: `spread ... vs slice() vs splice(0) vs concat() vs JSON.parse(JSON.stringify()) vs Custom function vs Lodash.cloneDeep() vs jQuery.extend(true)`

Created: 4 years ago by: Guest

Go to the latest result

HTML Preparation code:

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js" integrity="sha512-894YE6QWD5I59HgZOGReFYm4dnWc1Qt5NtvYSaNcOP+u1T9qYdvdihz0PPSiiqn/+/3e7Jo4EaG7TubfWGUrMQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js" integrity="sha512-WFN04846sdKMIP5LKNphMaWzU7YpMyCU245etK3g/2ARYbPK9Ub18eG+ljU96qKRCWh+quCY7yefSmlkQw1ANQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

Tests:

spread ...
const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true" // Shallow copies: [], {}, function () {} const arr2 = [ ...arr1 ];
slice()
const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true" // Shallow copies: [], {}, function () {} const arr2 = arr1.slice();
splice(0)
const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true" // Shallow copies: [], {}, function () {} const arr2 = arr1.splice(0);
concat()
const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true" // Shallow copies: [], {}, function () {} const arr2 = arr1.concat();
JSON.parse(JSON.stringify())
const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true", [], {} // Shallow copies: function () {} const arr2 = JSON.parse(JSON.stringify(arr1));
Custom function
function copy(aObject) { // Prevent undefined objects // if (!aObject) return aObject; let bObject = Array.isArray(aObject) ? [] : {}; let value; for (const key in aObject) { // Prevent self-references to parent object // if (Object.is(aObject[key], aObject)) continue; value = aObject[key]; bObject[key] = (typeof value === "object") ? copy(value) : value; } return bObject; } const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true", [], {}, function () {} const arr2 = copy(arr1);
Lodash.cloneDeep()
const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true", [], {}, function () {} const arr2 = _.cloneDeep(arr1);
jQuery.extend(true)
const arr1 = [ true, 1, "true", [], {}, function () {} ]; // Deep copies: true, 1, "true", [], {}, function () {} const arr2 = jQuery.extend(true, [], arr1);

Historical Performance Data aggregated from 154 community runs

Desktop Results:

Chrome 106 runs

slice()

40.1M/s

spread ...

36.9M/s

concat()

32.2M/s

splice(0)

29.2M/s

JSON.parse(JSON.stringify())

2.0M/s

Custom function

1.6M/s

Lodash.cloneDeep()

1.1M/s

jQuery.extend(true)

1.1M/s

Fastest: slice() (37.7x faster)

View exact numbers

✓ slice(): 40,103,256 ops/sec
• spread ...: 36,896,952 ops/sec
• concat(): 32,238,120 ops/sec
• splice(0): 29,242,748 ops/sec
• JSON.parse(JSON.stringify()): 1,960,636 ops/sec
• Custom function: 1,582,132 ops/sec
• Lodash.cloneDeep(): 1,130,643 ops/sec
• jQuery.extend(true): 1,063,475 ops/sec

Firefox 37 runs

slice()

26.2M/s

concat()

23.3M/s

spread ...

16.1M/s

splice(0)

15.6M/s

Custom function

2.4M/s

JSON.parse(JSON.stringify())

1.6M/s

Lodash.cloneDeep()

1.3M/s

jQuery.extend(true)

1.1M/s

Fastest: slice() (24.1x faster)

View exact numbers

✓ slice(): 26,225,306 ops/sec
• concat(): 23,272,356 ops/sec
• spread ...: 16,087,870 ops/sec
• splice(0): 15,555,317 ops/sec
• Custom function: 2,350,009 ops/sec
• JSON.parse(JSON.stringify()): 1,561,596 ops/sec
• Lodash.cloneDeep(): 1,291,071 ops/sec
• jQuery.extend(true): 1,086,476 ops/sec

Safari 5 runs

spread ...

25.8M/s

slice()

21.7M/s

splice(0)

14.5M/s

concat()

9.9M/s

JSON.parse(JSON.stringify())

1.7M/s

Lodash.cloneDeep()

1.4M/s

Custom function

1.4M/s

jQuery.extend(true)

898K/s

Fastest: spread ... (28.7x faster)

View exact numbers

✓ spread ...: 25,791,594 ops/sec
• slice(): 21,696,644 ops/sec
• splice(0): 14,547,287 ops/sec
• concat(): 9,881,104 ops/sec
• JSON.parse(JSON.stringify()): 1,707,640 ops/sec
• Lodash.cloneDeep(): 1,444,146 ops/sec
• Custom function: 1,391,286 ops/sec
• jQuery.extend(true): 898,275 ops/sec

Mobile Results:

Chrome 6 runs

slice()

18.5M/s

spread ...

17.7M/s

concat()

16.0M/s

splice(0)

13.0M/s

JSON.parse(JSON.stringify())

993K/s

Custom function

787K/s

jQuery.extend(true)

581K/s

Lodash.cloneDeep()

565K/s

Fastest: slice() (32.6x faster)

View exact numbers

✓ slice(): 18,452,868 ops/sec
• spread ...: 17,681,648 ops/sec
• concat(): 15,965,518 ops/sec
• splice(0): 13,027,082 ops/sec
• JSON.parse(JSON.stringify()): 993,114 ops/sec
• Custom function: 786,716 ops/sec
• jQuery.extend(true): 581,072 ops/sec
• Lodash.cloneDeep(): 565,228 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 ...
slice()
splice(0)
concat()
JSON.parse(JSON.stringify())
Custom function
Lodash.cloneDeep()
jQuery.extend(true)

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Android 17; Mobile; rv:153.0) Gecko/153.0 Firefox/153.0

Browser/OS: Firefox Mobile 153 on Android

View result in a separate tab

slice()

13.8M/s

concat()

12.9M/s

splice(0)

11.3M/s

spread ...

10.5M/s

Custom function

1.5M/s

JSON.parse(JSON.stringify())

1.4M/s

jQuery.extend(true)

1.0M/s

Lodash.cloneDeep()

997K/s

View exact numbers

Test name	Executions per second
✓ slice()	13,774,245 Ops/sec
concat()	12,905,778 Ops/sec
splice(0)	11,328,506 Ops/sec
spread ...	10,519,873 Ops/sec
Custom function	1,469,194 Ops/sec
JSON.parse(JSON.stringify())	1,364,106 Ops/sec
jQuery.extend(true)	1,039,348 Ops/sec
Lodash.cloneDeep()	996,589 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Deep copy comparison (version: 0) Benchmark.js

Benchmarks for StackOverflow question on deep copy techniques https://stackoverflow.com/questions/7486085/copy-array-by-value/23536726#23536726

Comparing performance of: spread ... vs slice() vs splice(0) vs concat() vs JSON.parse(JSON.stringify()) vs Custom function vs Lodash.cloneDeep() vs jQuery.extend(true)

Created: 4 years ago by: Guest

Go to the latest result

spread ...

slice()

splice(0)

concat()

JSON.parse(JSON.stringify())

Custom function

Lodash.cloneDeep()

jQuery.extend(true)

Historical Performance Data aggregated from 154 community runs

Desktop Results:

Chrome 106 runs

Firefox 37 runs

Safari 5 runs

Mobile Results:

Chrome 6 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

Related benchmarks

Comparing performance of: `spread ... vs slice() vs splice(0) vs concat() vs JSON.parse(JSON.stringify()) vs Custom function vs Lodash.cloneDeep() vs jQuery.extend(true)`