clone

What is clone?

The clone npm package is a utility for cloning JavaScript objects. It can create deep copies of objects, arrays, dates, and other types, ensuring that changes to the cloned object do not affect the original. It is useful when you need to work with copies of data without altering the original source.

What are clone's main functionalities?

Cloning objects

This feature allows you to create a deep copy of an object, so that changes to the cloned object do not affect the original object.

{"const clone = require('clone');
const obj = { a: 1, b: { c: 2 } };
const objClone = clone(obj);
console.log(objClone); // { a: 1, b: { c: 2 } }
objClone.b.c = 3;
console.log(obj.b.c); // 2, original object is not affected"}

Cloning arrays

This feature allows you to create a deep copy of an array, including any nested arrays, without affecting the original array.

{"const clone = require('clone');
const arr = [1, 2, [3, 4]];
const arrClone = clone(arr);
console.log(arrClone); // [1, 2, [3, 4]]
arrClone[2][0] = 5;
console.log(arr[2][0]); // 3, original array is not affected"}

Cloning dates

This feature allows you to clone Date objects, creating a new instance that represents the same moment in time as the original.

{"const clone = require('clone');
const date = new Date();
const dateClone = clone(date);
console.log(dateClone); // date object representing the same moment in time
console.log(date === dateClone); // false, they are different instances"}

Other packages similar to clone

lodash.clonedeep

lodash.clonedeep is a method from the Lodash library that provides deep cloning of objects and arrays. It is similar to clone but is part of a larger utility library that offers a wide range of functions for manipulating and traversing data.

deep-copy

deep-copy is another npm package that offers deep cloning functionality. It supports cloning of complex objects, including those with circular references. It is similar to clone but also handles functions and symbols, which clone does not.

rfdc

rfdc (Really Fast Deep Clone) is a package that focuses on performance for deep cloning objects and arrays. It claims to be faster than other deep cloning methods, especially for large objects. Unlike clone, rfdc does not support cloning of functions, dates, regexes, maps, sets, blobs, filelists, image data, or array buffers.

README

clone

offers foolproof deep cloning of variables in JavaScript.

Installation

npm install clone

or

ender build clone

Example

var clone = require('clone');

var a, b;

a = { foo: { bar: 'baz' } };  // inital value of a

b = clone(a);                 // clone a -> b
a.foo.bar = 'foo';            // change a

console.log(a);               // show a
console.log(b);               // show b

This will print:

{ foo: { bar: 'foo' } }
{ foo: { bar: 'baz' } }

clone masters cloning simple objects (even with custom prototype), arrays, Date objects, and RegExp objects. Everything is cloned recursively, so that you can clone dates in arrays in objects, for example.

API

clone(val, circular)

• val -- the value that you want to clone, any type allowed

• circular -- boolean

  Call clone with circular set to false if you are certain that obj contains no circular references. This will give better performance if needed. There is no error if undefined or null is passed as obj.

clone.clonePrototype(obj)

• obj -- the object that you want to clone

Does a prototype clone as described by Oran Looney.

Circular References

var a, b;

a = { hello: 'world' };

a.myself = a;
b = clone(a);

console.log(b);

This will print:

{ hello: "world", myself: [Circular] }

So, b.myself points to b, not a. Neat!

Test

npm test

Caveat

Some special objects like a socket or process.stdout/stderr are known to not be cloneable. If you find other objects that cannot be cloned, please open an issue.

Bugs and Issues

If you encounter any bugs or issues, feel free to open an issue at github or send me an email to [e-mail]. I also always like to hear from you, if you’re using my code.

License

Copyright © 2011-2013 Paul Vorbach

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.