This is the fastest deep-clone implementation for JSON objects - faster than structuredClone, JSON.parse(JSON.stringify(obj)) and other implementations, according to www.measurethat.net.

This package is ESM-only.

• Dependencies: 0
• Bundle size (minified and gzipped): 316 Bytes
• Module count: 1

It avoids recursion in favor of a stack, in order to keep the memory usage low.

Performance comparison

Method	Ops/sec
This package (iterative deep clone)	3.560.061
recursive deep clone	3.476.448
fastest-json-copy v2	1.523.427
JSON.stringify	1.465.516
fastest-json-copy v1	1.320.249
jsondiffpatch.clone	1.245.459
structuredClone	789.100

Run it yourself: https://www.measurethat.net/Benchmarks/ShowResult/534839 (this package is deepCopyObjectIterative in that comparison).

When running the local benchmark, the results are very different and jsondiffpatch.clone becomes the fastest.

Installation

pnpm install fastest-deep-clone-json

or

npm install fastest-deep-clone-json

Usage

import { deepCloneJson } from 'fastest-deep-clone-json';

const obj = { a: 1, b: { c: 2 } };

const cloned = deepCloneJson(obj);

console.log(cloned); // { a: 1, b: { c: 2 } }

This library will only work with JSON-serialized objects. It does not handle data types like Date, Map, Set, BigInt, Symbol, Function etc etc. The goal is to provide the fastest deep-clone implementation for JSON objects.