deep-extend

What is deep-extend?

The deep-extend npm package is a utility for deep (recursive) extending of the properties of objects. It is useful for merging the contents of multiple objects into one. This can be particularly helpful when dealing with configurations or settings that need to be composed from multiple sources.

What are deep-extend's main functionalities?

Deep Merging of Objects

This feature allows you to merge multiple objects into a single object, combining and overriding properties as necessary. The properties from later objects will override those from earlier ones.

{"const deepExtend = require('deep-extend');
const obj1 = { a: 1, b: { c: 1 } };
const obj2 = { b: { d: 2 } };
const result = deepExtend({}, obj1, obj2);
console.log(result); // Output: { a: 1, b: { c: 1, d: 2 } }}

Other packages similar to deep-extend

lodash.merge

Lodash provides a method called merge which can recursively merge own and inherited enumerable string keyed properties of source objects into the destination object. It's similar to deep-extend but comes as part of the larger lodash utility library, which offers a wide range of functions for different purposes.

extend

The extend package is another utility that can merge objects but does not offer deep merge capabilities by default. It is less powerful for deep object merging compared to deep-extend but can be used for shallow merges.

merge-deep

Merge-deep is similar to deep-extend as it allows for deep merging of objects. It recursively merges own and inherited enumerable properties of source objects into the destination object, similar to deep-extend, and is a good alternative if deep-extend is not suitable for some reason.

README

Node.JS module “Deep Extend”

Recursive object extending.

Install

npm install deep-extend

Usage

var deepExtend = require('deep-extend');
var obj1 = {
	a: 1,
	b: 2,
	d: {
		a: 1,
		b: [],
		c: { test1: 123, test2: 321 }
	},
	f: 5,
	g: 123
};
var obj2 = {
	b: 3,
	c: 5,
	d: {
		b: { first: 'one', second: 'two' },
		c: { test2: 222 }
	},
	e: { one: 1, two: 2 },
	f: [],
	g: (void 0),
	h: /abc/g,
	f: null
};

deepExtend(obj1, obj2);

console.log(obj1);
/*
{ a: 1,
  b: 3,
  d:
   { a: 1,
     b: { first: 'one', second: 'two' },
     c: { test1: 123, test2: 222 } },
  f: null,
  g: undefined,
  c: 5,
  e: { one: 1, two: 2 },
  h: /abc/g }
*/