DEPRECATION NOTICE

After a few years since it's creation, fast-clone is no longer the fastest cloning library on npm. Alternative packages have caught up and overtaken it. I had a last stab at optimising it while adding new features but alas optimising for performance further meant sacrificing features (and vice-versa). So I've decided to hand over the fast-clone npm namespace to a more worthy contender. rfdc (really fast deep clone) is exactly what it's initialism means: really fast.

The fastest deep cloning function on NPM that supports the following types:

• Objects (POJOs, null, undefined)
• Arrays
• Dates
• Regular Expressions
• Strings
• Numbers (NaN, Positive Infinity, Negative Infinity)
• Booleans

Speed Comparison

Average runtime of various NPM clone libraries on a large complex object loaded from json files of varying sizes ranging from 3.5 MB to 15 MB.

Library	7.15 MB
✔ fast-clone	120 ms
✘ deepClone	138 ms
✘ lodash.cloneDeep	155 ms
✘ snapshot	1,127 ms
✘ angular.copy	1,942 ms
✘ clone	2,085 ms

Installation

NPM

npm install fast-clone --save

Yarn

yarn add fast-clone

Usage

Fast-clone is a UMD module so you can use it in Node.js, or in Browser either using Browserfy/Webpack, or by using the global clone function if not using a module loader.

TypeScript

import clone = require('fast-clone');

JavaScript

const clone = require('fast-clone');

const a = {
	name: 'Natasha Rominov',
	age: 30,
	skills: [
		'Pistols',
		'Espionage'
	],
	dateOfBirth: new Date('1986-05-21T00:00:00.000Z')
};

const b = clone(a);

b.skills.push('That grabby thing she does with her legs');

console.log(a.skills)
console.log(b.skills);

Output will be:

['Pistols', 'Espionage']
['Pistols', 'Espionage', 'That grabby thing she does with her legs']

Contributing

Got an issue or a feature request? Log it.

Pull-requests are also welcome. 😸