Install

npm install @visulima/deep-clone

yarn add @visulima/deep-clone

pnpm add @visulima/deep-clone

Usage

Copy or deep clone an input value to an arbitrary depth. The function accepts both objects and primitives.

import deepClone from "@visulima/deep-clone";

const cloned = deepClone({ a: 1, b: { c: 2 } });

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

API

deepClone(input, options?)

input

Type: any

The input value to copy.

options

Type: object

strict

Type: boolean

Default: false

If true, it will copy all properties, including non-enumerable ones and symbols.

handlers

Type: object

A set of custom handlers for specific type of value. Each handler is a function that takes the original value and returns a new value or throws an error if the value is not supported.

• Array: InternalHandler<unknown[]>;
• ArrayBuffer: InternalHandler;
• Blob: InternalHandler;
• DataView: InternalHandler;
• Date: InternalHandler;
• Error: InternalHandler;
• Float32Array: InternalHandler;
• Float64Array: InternalHandler;
• Int8Array: InternalHandler;
• Int16Array: InternalHandler;
• Int32Array: InternalHandler;
• Map: InternalHandler<Map<unknown, unknown>>;
• Object: InternalHandler<Record<string, unknown>>;
• Promise: InternalHandler<Promise>;
• RegExp: InternalHandler;
• Set: InternalHandler<Set>;
• WeakMap: InternalHandler<WeakMap<any, unknown>>;
• WeakSet: InternalHandler<WeakSet>;

Utils

copyOwnProperties(input)

Copy all properties contained on the object.

import { copyOwnProperties } from "@visulima/deep-clone/utils";

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

const copy = copyOwnProperties(obj);

console.log(copy); // => {a: 1, b: 2}

getCleanClone(input)

Get an empty version of the object with the same prototype it has.

import { getCleanClone } from "@visulima/deep-clone/utils";

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

const clean = getCleanClone(obj);

console.log(clean); // => {}

Notes

• List of supported values/types:

  • undefined (original value is returned)
  • null (original value is returned)
  • boolean/Boolean (original value is returned)
  • string/String (original value is returned)
  • number/Number (original value is returned)
  • function
  • Object
  • Date
  • RegExp
  • Set
  • Map
  • Error
  • URIError
  • ReferenceError
  • SyntaxError
  • RangeError
  • EvalError
  • TypeError
  • System Error (Node.js)
  • Array
  • Int8Array
  • Uint8Array
  • Uint8ClampedArray
  • Init16Array
  • Uint16Array
  • Int32Array
  • Uint32Array
  • Float32Array
  • Float64Array
  • Buffer (Node.js)
  • DataView
  • Blob

• List of unsupported values/types:

  • DOMElement: to copy DOM elements, use element.cloneNode().
  • Symbol
  • WeakMap
  • WeakSet
  • File
  • FileList
  • ImageData
  • ImageBitmap
  • Promise
  • SharedArrayBuffer

• The implementation can handle circular references.

• If a Number, String, or Boolean object is encountered, the value is cloned as a primitive. This behavior is intentional. The implementation is opinionated in wanting to avoid creating numbers, strings, and booleans via the new operator and a constructor.

• The implementation only checks whether basic Objects, Arrays, and class instances are extensible, sealed, and/or frozen.

• functions are not cloned; their reference is copied.

• The implementation supports custom error types which are Error instances (e.g., ES2015 subclasses).

Benchmarks

Note:

It is true that jsondiffpatch.clone() from jsondiffpatch is faster than @visulima/deep-clonse in this particular benchmark, but it cannot handle as many situations as @visulima/deep-clonse can.

It is true that fastest-json-copy is faster than @visulima/deep-clonse in this particular benchmark. Also, fastest-json-copy has such huge limitations that it is rarely useful. For example, it treats things like Date and Map instances the same as empty {}. It can't handle circular references.

plain-object-clone is also really limited in capability.

Supported Node.js Versions

Libraries in this ecosystem make the best effort to track Node.js’ release schedule. Here’s a post on why we think this is important.

Contributing

If you would like to help take a look at the list of issues and check our Contributing guild.

Note: please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.

Credits

• Daniel Bannert
• All Contributors

License

The visulima deep-clone is open-sourced software licensed under the MIT