deepcopy

What is deepcopy?

The 'deepcopy' npm package is used to create deep copies of JavaScript objects. This means that it recursively copies all nested objects and arrays, ensuring that the new object is completely independent of the original.

What are deepcopy's main functionalities?

Deep Copy of Objects

This feature allows you to create a deep copy of an object, ensuring that nested objects are also copied.

const deepcopy = require('deepcopy');
const original = { a: 1, b: { c: 2 } };
const copy = deepcopy(original);
console.log(copy); // { a: 1, b: { c: 2 } }

Deep Copy of Arrays

This feature allows you to create a deep copy of an array, ensuring that nested arrays and objects are also copied.

const deepcopy = require('deepcopy');
const original = [1, [2, 3], { a: 4 }];
const copy = deepcopy(original);
console.log(copy); // [1, [2, 3], { a: 4 }]

Handling Circular References

This feature allows you to handle circular references in objects, ensuring that the deep copy process does not result in an infinite loop.

const deepcopy = require('deepcopy');
const original = { a: 1 };
original.b = original;
const copy = deepcopy(original);
console.log(copy); // { a: 1, b: [Circular] }

Other packages similar to deepcopy

lodash

Lodash is a popular utility library that provides a wide range of functions for manipulating arrays, objects, and other data types. It includes a `cloneDeep` function that performs deep copying similar to `deepcopy`. However, Lodash offers many additional utilities beyond deep copying.

rfdc

The 'rfdc' (Really Fast Deep Clone) package is designed for performance and provides a very fast way to deep clone objects. It is similar to `deepcopy` in functionality but is optimized for speed.

clone-deep

The 'clone-deep' package is another utility for deep cloning objects and arrays. It is similar to `deepcopy` but offers additional options for customizing the cloning process.

README

deepcopy.js

deep copy data

Installation

$ npm install deepcopy

Usage

node.js

via ES Modules

import deepcopy from 'deepcopy';

via CommonJS

const deepcopy = require('deepcopy');

browser

via module

<script type="module">
  import deepcopy from "./dist/deepcopy.min.mjs";
</script>

via script

<script src="./dist/deepcopy.min.js"></script>

Example

basic usage:

const src = {
  desserts: [
    { name: 'cake'      },
    { name: 'ice cream' },
    { name: 'pudding'   }
  ]
};

const dist = deepcopy(src);

src.desserts = null;

console.log(src);   // { desserts: null }
console.log(dist);  // { desserts: [ { name: 'cake' }, { name: 'ice cream' }, { name: 'pudding' } ] }

customize deepcopy:

function MyClass(id) {
  this._id = id;
}

const src = {
  myClasses: [
    new MyClass(1),
    new MyClass(2),
    new MyClass(3)
  ]
};

const dest = deepcopy(base, {
  customizer(value) {
    if (target.constructor === MyClass) {
      return new MyClass(target._id);
    }
  }
});

src.myClasses = null;

console.log(src);   // { myClasses: null }
console.log(dest);  // { myClasses: [ MyClass { _id: 1 }, MyClass { _id: 2 }, MyClass { _id: 3 } ] }

Explanation of build files

• deepcopy.mjs
  • library bundled
  • ES Modules
• deepcopy.min.mjs
  • minified deepcopy.mjs
• deepcopy.js
  • library bundled
  • UMD builds
• deepcopy.min.js
  • minified deepcopy.js
• deepcopy.legacy.js
  • compiled for old browsers with @babel/preset-env
    • IE >= 11
    • Android >= 4.4.4
  • library bundled
  • UMD builds
• deepcopy.legacy.min.js
  • minified deepcopy.legacy.js

scripts are put in dist directory.

Functions

deepcopy(value[, options])

• value
  • *
    • target value
• options
  • Object|Function
    • Object - pass options
    • Function - use as customize function
• return
  • * - copied value

Supported types and copy operation

type	operation
ArrayBuffer	deep copy
Boolean	deep copy
Buffer	deep copy	node.js only
DataView	deep copy
Date	deep copy
Number	deep copy
RegExp	deep copy
String	deep copy
Float32Array	deep copy
Float64Array	deep copy
Int16Array	deep copy
Int32Array	deep copy
Int8Array	deep copy
Uint16Array	deep copy
Uint32Array	deep copy
Uint8Array	deep copy
Uint8ClampedArray	deep copy
boolean	deep copy
null	deep copy
number	deep copy
string	deep copy
symbol	deep copy
undefined	deep copy
Arguments	deep copy	recursively, copy as Array
Array	deep copy	recursively
Map	deep copy	recursively
Object	deep copy	recursively
Set	deep copy	recursively
Array Iterator	shallow copy
Map Iterator	shallow copy
Promise	shallow copy
Set Iterator	shallow copy
String Iterator	shallow copy
function	shallow copy
global	shallow copy	window, global, self, etc.
WeakMap	shallow copy
WeakSet	shallow copy

Test

$ npm install
$ npm test

Contributors

• kjirou

License

The MIT license.