Run results for: Deep Clone vs JSON.Stringify

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser: Chrome 137

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

DeepClone

246K/s

JSON.stringify

139K/s

View exact numbers

Test name	Executions per second
✓ DeepClone	246,233 Ops/sec
JSON.stringify	138,912 Ops/sec

Script Preparation code:

var obj = {};
var objCount = 100;

for (let i = 0; i < objCount; i++) {
    obj[i] = [1, 2, 3];
}

function deepClone(objIn) {
    let copy;

    if (objIn === null || typeof objIn !== 'object') {
        return obj;
    }

    if (objIn instanceof Array) {
        copy = [];
        for (let i = 0, len = objIn.length; i < len; i++) {
            copy[i] = deepClone(objIn[i]);
        }
        return copy;
    }

    if (objIn instanceof Object) {
        copy = {};
        for (const attr in objIn) {
            if (objIn.hasOwnProperty(attr)) {
                copy[attr] = deepClone(objIn[attr]);
            }
        }
        return copy;
    }

}

Tests:

DeepClone
var clone = deepClone(obj);
JSON.stringify
var clone = JSON.parse(JSON.stringify(obj));