merge-deep

What is merge-deep?

The merge-deep npm package is a utility for deeply merging objects in JavaScript. It is useful for combining configurations, options, or states in a way that nested properties are not lost but instead merged together.

What are merge-deep's main functionalities?

Deep merging of objects

This feature allows you to deeply merge multiple objects into one. It recursively merges own and inherited enumerable properties of source objects into the destination object, skipping source properties that resolve to `undefined`.

{"const mergeDeep = require('merge-deep');\nconst object1 = { a: { b: 1 } };\nconst object2 = { a: { c: 2 }, d: 3 };\nconst result = mergeDeep(object1, object2);\nconsole.log(result); // Output: { a: { b: 1, c: 2 }, d: 3 }"}

Merging with array concatenation

Merge-deep can also merge arrays by concatenating them. This is useful when you want to combine arrays from different objects without losing any elements.

{"const mergeDeep = require('merge-deep');\nconst object1 = { a: [1, 2], b: 'one' };\nconst object2 = { a: [3, 4], b: 'two' };\nconst result = mergeDeep(object1, object2);\nconsole.log(result); // Output: { a: [1, 2, 3, 4], b: 'two' }"}

Customizing merge behavior

Users can define a custom merge function to control how merging is done. This is particularly useful when the default behavior of merge-deep does not suit the specific needs of your application.

{"const mergeDeep = require('merge-deep');\nfunction customMerge(a, b) {\n  return Array.isArray(a) ? a.concat(b) : undefined;\n}\nconst object1 = { a: [1], b: [2] };\nconst object2 = { a: [3], b: [4] };\nconst result = mergeDeep({ customMerge }, object1, object2);\nconsole.log(result); // Output: { a: [1, 3], b: [2, 4] }"}

Other packages similar to merge-deep

lodash.merge

Lodash's merge function is similar to merge-deep as it allows for deep merging of objects. Lodash is a larger utility library, and its merge function is one of many utilities it provides. It is well-tested and widely used in the JavaScript community.

deepmerge

Deepmerge is another npm package that provides deep merging capabilities. It is similar to merge-deep but offers additional options for customizing the merge behavior, such as whether to clone or not clone the source objects, and how to handle merging arrays.

extend

The extend package is a port of the jQuery extend method that can also perform deep merging of objects. It is less specialized than merge-deep and deepmerge, but it is still a viable option for users who prefer a jQuery-like API.

README

merge-deep

Recursively merge values in a javascript object.

Based on mout's implementation of merge

Install with npm

npm i merge-deep --save

Usage

var merge = require('merge-deep');

merge({a: {b: {c: 'c', d: 'd'}}}, {a: {b: {e: 'e', f: 'f'}}});
//=> { a: { b: { c: 'c', d: 'd', e: 'e', f: 'f' } } }

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

Related projects

These are other projects I maintain:

• extend-shallow
• flatten-object
• for-in
• for-own
• has-any
• has-value
• is-number
• is-plain-object
• mixin-deep
• mixin-object
• object-length
• omit-empty
• reduce-object

Run tests

Install dev dependencies:

npm i -d && npm test

License

Copyright (c) 2015 Jon Schlinkert
Released under the MIT license

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This file was generated by verb on February 25, 2015.