node.extend

What is node.extend?

The node.extend package is a simple utility for deep and shallow extending (merging) of objects. It is useful for combining multiple objects into one, copying properties from one object to another, and creating new objects with inherited properties.

What are node.extend's main functionalities?

Shallow Extend

This feature allows you to perform a shallow merge of multiple objects. In the example, properties from obj2 overwrite those in obj1 where they conflict.

const extend = require('node.extend');
const obj1 = { a: 1, b: 2 };
const obj2 = { b: 3, c: 4 };
const result = extend({}, obj1, obj2);
console.log(result); // { a: 1, b: 3, c: 4 }

Deep Extend

This feature allows you to perform a deep merge of multiple objects. Nested objects are merged recursively. In the example, the nested properties of obj2 overwrite those in obj1 where they conflict.

const extend = require('node.extend');
const obj1 = { a: 1, b: { x: 1, y: 2 } };
const obj2 = { b: { y: 3, z: 4 }, c: 5 };
const result = extend(true, {}, obj1, obj2);
console.log(result); // { a: 1, b: { x: 1, y: 3, z: 4 }, c: 5 }

Clone Object

This feature allows you to create a deep clone of an object. The example demonstrates cloning an object with nested properties.

const extend = require('node.extend');
const obj = { a: 1, b: { x: 1, y: 2 } };
const clone = extend(true, {}, obj);
console.log(clone); // { a: 1, b: { x: 1, y: 2 } }

Other packages similar to node.extend

lodash

Lodash is a modern JavaScript utility library delivering modularity, performance, and extras. It provides a wide range of utility functions, including deep and shallow merging of objects. Compared to node.extend, lodash offers a more extensive set of utilities beyond object merging.

merge

The merge package is a simple utility for merging objects. It supports both deep and shallow merging. Compared to node.extend, merge is more focused on object merging and does not provide additional utilities.

deepmerge

Deepmerge is a library for deep merging of JavaScript objects. It is specifically designed for deep merging and handles arrays and objects recursively. Compared to node.extend, deepmerge is more specialized for deep merging scenarios.

README

node.extend

A port of jQuery.extend that actually works on node.js

Description

None of the existing ones on npm really work therefore I ported it myself.

Usage

To install this module in your current working directory (which should already contain a package.json), run

npm install node.extend

You can additionally just list the module in your package.json and run npm install.

Then, require this package where you need it:

var extend = require('node.extend');

The syntax for merging two objects is as follows:

var destObject = extend({}, sourceObject);
// Where sourceObject is the object whose properties will be copied into another.
// NOTE: In this situation, this is not a deep merge. See below on how to handle a deep merge.

For information about how the clone works internally, view source in lib/extend.js or checkout the doc from jQuery

A Note About Deep Merge (avoiding pass-by-reference cloning)

In order to force a deep merge, when extending an object, you must pass boolean true as the first argument to extend:

var destObject = extend(true, {}, sourceObject);
// Where sourceObject is the object whose properties will be copied into another.

See this article for more information about the need for deep merges in JavaScript.

Credit

• Jordan Harband @ljharb

License

Copyright 2011, John Resig Dual licensed under the MIT or GPL Version 2 licenses. http://jquery.org/license