lodash.mergewith

What is lodash.mergewith?

The lodash.mergewith package is a utility library that provides a method for deep merging objects. It allows for custom merge functions to be specified, enabling more complex merging strategies than the default deep merge.

What are lodash.mergewith's main functionalities?

Deep Merging Objects

This feature allows for deep merging of objects with a custom merge function. In this example, arrays are concatenated instead of being replaced.

const _ = require('lodash.mergewith');

const object = { 'a': [{ 'b': 2 }, { 'd': 4 }] };
const other = { 'a': [{ 'c': 3 }, { 'e': 5 }] };

function customizer(objValue, srcValue) {
  if (Array.isArray(objValue)) {
    return objValue.concat(srcValue);
  }
}

const result = _.mergeWith(object, other, customizer);
console.log(result); // { 'a': [{ 'b': 2, 'c': 3 }, { 'd': 4, 'e': 5 }] }

Other packages similar to lodash.mergewith

deepmerge

The deepmerge package is another utility for deep merging objects. It provides a simple API for merging objects and arrays, but does not support custom merge functions out of the box. It is useful for straightforward deep merges without the need for custom logic.

merge-options

The merge-options package allows for deep merging of objects with options for customizing the merge behavior. It is similar to lodash.mergewith in that it supports custom merge functions, but it provides a different API and additional options for controlling the merge process.

README

lodash.mergewith v4.3.4

The lodash method _.mergeWith exported as a Node.js module.

Installation

Using npm:

$ {sudo -H} npm i -g npm
$ npm i --save lodash.mergewith

In Node.js:

var mergeWith = require('lodash.mergewith');

See the documentation or package source for more details.