Copy anything 🎭

npm i copy-anything

An optimised way to copy'ing (cloning) an object or array. A small and simple integration.

Motivation

I created this package because I tried a lot of similar packages that do copy'ing/cloning. But all had its quirks, and all of them break things they are not supposed to break... 😞

I was looking for:

• a simple copy/clone function
• has to be fast!
• props must lose any reference to original object
• works with arrays and objects in arrays!
• does not break special class instances　‼️

This last one is crucial! So many libraries use custom classes that create objects with special prototypes, and such objects all break when trying to copy them inproperly. So we gotta be careful!

copy-anything will copy objects and nested properties, but only as long as they're "plain objects". As soon as a sub-prop is not a "plain object" and has a special prototype, it will copy that instance over "as is". ♻️

Meet the family

• copy-anything 🎭
• merge-anything 🥡
• filter-anything ⚔️
• find-and-replace-anything 🎣
• compare-anything 🛰
• flatten-anything 🏏
• is-what 🙉

Usage

import copy from 'copy-anything'

const original = {name: 'Ditto', type: {water: true}}
const copy = copy(original)

// now if we change a nested prop like the type:
copy.type.water = false
copy.type.fire = true // new prop

// then the original object will still be the same:
(original.type.water === true)
(original.type.fire === undefined)

Works with arrays

It will also clone arrays, as well as objects inside arrays! 😉

import copy from 'copy-anything'

const original = [{name: 'Squirtle'}]
const copy = copy(original)

// now if we change a prop in the array like so:
copy[0].name = 'Wartortle'
copy.push({name: 'Charmander'}) // new item

// then the original array will still be the same:
(original[0].name === 'Squirtle')
(original[1] === undefined)

Source code

The source code is literally just these lines. Most of the magic comes from the isPlainObject function from the is-what library.

import { isPlainObject } from 'is-what'

export default function copy (target) {
  if (isArray(target)) return target.map(i => copy(i))
  if (!isPlainObject(target)) return target
  return Object.keys(target)
    .reduce((carry, key) => {
      const val = target[key]
      carry[key] = copy(val)
      return carry
    }, {})
}