Run results for: Deep copy comparison

Test name	Executions per second
✓ spread ...	20,113,854 Ops/sec
splice(0)	8,096,175 Ops/sec
concat()	3,145,636 Ops/sec
slice()	2,814,929 Ops/sec
Custom function	1,917,363 Ops/sec
jQuery.extend(true)	1,031,680 Ops/sec
Lodash.cloneDeep()	752,352 Ops/sec
JSON.parse(JSON.stringify())	487,469 Ops/sec

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);

Run results for: Deep copy comparison

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

spread ...

slice()

splice(0)

concat()

JSON.parse(JSON.stringify())

Custom function

Lodash.cloneDeep()

jQuery.extend(true)