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Mergician

Uniquely flexible and light-weight utility for cloning and deep (recursive) merging of JavaScript objects. Supports descriptor values, accessor functions, and custom prototypes. Provides advanced options for customizing the clone/merge process.

Install / Use

/learn @jhildenbiddle/Mergician

README

Mergician

NPM GitHub Workflow Status (main) Codacy code quality License: MIT jsDelivr Sponsor this project

Mergician is a uniquely flexible and light-weight utility for cloning and deep (recursive) merging of JavaScript objects.

Unlike native methods and other utilities, Mergician faithfully clones and merges objects by properly handling descriptor values, accessor functions, and prototype properties while offering advanced options for customizing the clone/merge process.

Features

  • Deep (recursive) clone/merge JavaScript objects
  • Generates new object without modifying source object(s)
  • Clone/merge enumerable and non-enumerable properties
  • Clone/merge property descriptor values
  • Retain, skip, or convert accessor functions to static values
  • Inspect, filter, and modify properties
  • Merge, skip, or hoist prototype properties
  • Merge or skip key intersections, unions, and differences
  • Merge, sort, and remove duplicate array items
  • IntelliSense / code hinting support
  • TypeScript support
  • Lightweight (2k min+gzip) and dependency-free

Platform Support

<img src="https://raw.githubusercontent.com/jhildenbiddle/mergician/main/docs/assets/img/node.svg" valign="middle" alt=""> <span valign="middle">Node 10+</span> <br> <img src="https://raw.githubusercontent.com/jhildenbiddle/mergician/main/docs/assets/img/chrome.svg" valign="middle" alt=""> <span valign="middle">Chrome 61+</span> <br> <img src="https://raw.githubusercontent.com/jhildenbiddle/mergician/main/docs/assets/img/edge.svg" valign="middle" alt=""> <span valign="middle">Edge 16+</span> <br> <img src="https://raw.githubusercontent.com/jhildenbiddle/mergician/main/docs/assets/img/firefox.svg" valign="middle" alt=""> <span valign="middle">Firefox 60+</span> <br> <img src="https://raw.githubusercontent.com/jhildenbiddle/mergician/main/docs/assets/img/safari.svg" valign="middle" alt=""> <span valign="middle">Safari 10.1+</span>

Examples

Basic object cloning using default options:

// ES module shown. CommonJS module also available (see below).
import { mergician } from 'mergician';

const obj1 = { a: [1, 1], b: { c: 1, d: 1 } };
const clonedObj = mergician({}, obj1);

// Results
console.log(clonedObj); // { a: [1, 1], b: { c: 1, d: 1 } }
console.log(clonedObj === obj1); // false
console.log(clonedObj.a === obj1.a); // false
console.log(clonedObj.b === obj1.b); // false

Advanced object merging using custom options:

// ES module shown. CommonJS module also available (see below).
import { mergician } from 'mergician';

const obj1 = { a: [1, 1], b: { c: 1, d: 1 } };
const obj2 = { a: [2, 2], b: { c: 2 } };
const obj3 = { e: 3 };

const mergedObj = mergician({
  skipKeys: ['d'],
  appendArrays: true,
  dedupArrays: true,
  filter({ depth, key, srcObj, srcVal, targetObj, targetVal }) {
    if (key === 'e') {
      targetObj['hello'] = 'world';
      return false;
    }
  }
})(obj1, obj2, obj3);

// Result
console.log(mergedObj); // { a: [1, 2], b: { c: 2 }, hello: 'world' }

Installation

NPM

npm install mergician
// ES module
import { mergician } from 'mergician';
// CommonJS module
const { mergician } = require('mergician');

CDN

Available on jsdelivr (below), unpkg, and other CDN services that auto-publish npm packages.

💡 Note the @ version lock in the URLs below. This prevents breaking changes in future releases from affecting your project and is therefore the safest method of loading dependencies from a CDN. When a new major version is released, you will need to manually update your CDN URLs by changing the version after the @ symbol.

// ES module @ latest v2.x.x
import { mergician } from 'https://cdn.jsdelivr.net/npm/mergician@2';

Usage & Options

See the documentation site for details.

Sponsorship

A sponsorship is more than just a way to show appreciation for the open-source authors and projects we rely on; it can be the spark that ignites the next big idea, the inspiration to create something new, and the motivation to share so that others may benefit.

If you benefit from this project, please consider lending your support and encouraging future efforts by becoming a sponsor.

Thank you! 🙏🏻

Contact & Support

  • Follow 👨🏻‍💻 @jhildenbiddle on Twitter and GitHub for announcements
  • Create a 💬 GitHub issue for bug reports, feature requests, or questions
  • Add a ⭐️ star on GitHub and 🐦 tweet to promote the project
  • Become a 💖 sponsor to support the project and future efforts

License

This project is licensed under the MIT license.

Copyright (c) John Hildenbiddle (@jhildenbiddle)

View on GitHub
GitHub Stars84
CategoryCustomer
Updated5mo ago
Forks3

Languages

JavaScript

Security Score

97/100

Audited on Oct 11, 2025

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