DeepClone-js: JS utility with circular replacer

README.md

DeepClone-js

Utility to clean up circular references while creating a new reference of an object performing a deep copy (as oposite to a shallow copy). Bear in mind it doesn't work with some data types: Date, Map, RegExp, Set, TypedArray...

📦 Install

npm i -S gist:0bce1161cfd2aa91ae7cad9abb42c342

Usage

import { deepClone } from 'deepclone-js'

const source = {
  b: 1,
}

const original = { ...source }
original.c = original // 👉🏼 Circular reference

const copy = deepClone(original)
// expect(copy).toEqual(source) // -> true

deepClone.js

/**
 * @param {Object} object
 * @returns {Boolean}
 */
const isFalsy /* So, it's not an object */ = object => !object

/**
 * Matches object type
 * @param {Object} object
 * @returns {Boolean}
 */
export const isObjectType = object => !!(typeof object).match(/object/)
/**
* @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Cyclic_object_value#Examples
* @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet
*/
const getCircularReplacer = () => {
  const seen = new WeakSet()
  return (_key, value) => {
    if (typeof value === 'object' && value !== null) {
      if (seen.has(value)) {
        return
      }
      seen.add(value)
    }
    return value
  }
}

/**
 * @param {Object} object The object to be cloned
 * @returns A copied value representing a new reference and discarding circular references
 */
export const deepClone = object => {
  if (isFalsy(object)) return {}
  if (!isObjectType(object)) return object
  return JSON.parse(JSON.stringify(object, getCircularReplacer()))
}

package.json

{
  "version": "0.0.3",
  "name": "deepclone-js",
  "main": "deepClone.js"
}