defu

What is defu?

The defu npm package is a utility for performing default deep assignments on objects. It is commonly used to merge a set of objects into a single object, where the properties of later objects will overwrite those of earlier ones if they exist. This is particularly useful for managing configurations or options objects where default values need to be easily overridden by user inputs or other sources.

What are defu's main functionalities?

Deep Object Merging

This feature allows for the deep merging of objects. Properties from the second object (`objB`) are merged into the first object (`objA`), with nested properties being merged rather than replaced. This is useful for combining configurations with nested structures.

{"const defu = require('defu');\nconst objA = { foo: { bar: true } };\nconst objB = { foo: { baz: false }, qux: 1 };\nconst result = defu(objA, objB);\nconsole.log(result); // Output: { foo: { bar: true, baz: false }, qux: 1 }"}

Array Merging

This demonstrates how `defu` can be used to merge arrays contained within objects. Instead of replacing the array in `arrA` with the one in `arrB`, `defu` concatenates the arrays, preserving the order and contents of both.

{"const defu = require('defu');\nconst arrA = { arr: [1, 2] };\nconst arrB = { arr: [3, 4] };\nconst result = defu(arrA, arrB);\nconsole.log(result); // Output: { arr: [1, 2, 3, 4] }"}

Other packages similar to defu

lodash.merge

Lodash's merge function offers similar deep merging capabilities as defu. However, lodash is a much larger library with a wide range of utilities beyond object merging. While defu is focused and lightweight, lodash provides a comprehensive suite of tools that may be beneficial for projects needing more than just object merging.

deepmerge

Deepmerge is another npm package that specializes in merging objects deeply. Like defu, it is focused on this specific task, but it offers more customization options, such as array merging strategies and cloning. This makes deepmerge a more flexible choice for complex merging needs, though it might be slightly more complex to use than defu.

README

🇩 defu

Recursively assign default properties. Lightweight and Fast!

Install

Install package:

npm install defu

OR

yarn add defu

Usage

const options = defu (object, ...defaults)

Most left arguments have more perioriry when assigning defaults.

Arguments

• object (Object): The destination object.
• source (Object): The source object.

const defu = require('defu')

console.log(defu({ 'a': { 'b': 2 } }, { 'a': { 'b': 1, 'c': 3 } }))
// => { a: { b: 2, c: 3 } }

Remarks

• object and defaults are not modified
• null values are skipped same as defaults-deep. Please use either omit-deep or lodash.defaultsdeep if you need to to preserve.
• Assignment of __proto__ and constructor keys will be skipped to prevent security issues with object pollution.

License

MIT. Made with 💖

Changelog

2.0.4 (2020-05-22)

Bug Fixes

• correct path to types (33d4bf0)