deepmerge-ts

What is deepmerge-ts?

The deepmerge-ts package is a TypeScript library designed to deeply merge two or more objects. It ensures type safety and is particularly useful for complex nested objects where shallow merging would not suffice.

What are deepmerge-ts's main functionalities?

Basic Deep Merge

This feature allows you to deeply merge two objects. In this example, obj1 and obj2 are merged such that the nested properties are combined.

const deepmerge = require('deepmerge-ts').default;
const obj1 = { a: 1, b: { c: 2 } };
const obj2 = { b: { d: 3 } };
const result = deepmerge(obj1, obj2);
console.log(result); // { a: 1, b: { c: 2, d: 3 } }

Array Merge

This feature allows you to merge arrays within objects. In this example, the arrays in obj1 and obj2 are concatenated.

const deepmerge = require('deepmerge-ts').default;
const obj1 = { a: [1, 2, 3] };
const obj2 = { a: [4, 5] };
const result = deepmerge(obj1, obj2);
console.log(result); // { a: [1, 2, 3, 4, 5] }

Custom Merge Function

This feature allows you to define custom merge functions for specific keys. In this example, the custom merge function concatenates arrays for the key 'a'.

const deepmerge = require('deepmerge-ts').default;
const customMerge = (key, options) => {
  if (key === 'a') {
    return (a, b) => a.concat(b);
  }
  return undefined;
};
const obj1 = { a: [1, 2, 3], b: { c: 2 } };
const obj2 = { a: [4, 5], b: { d: 3 } };
const result = deepmerge(obj1, obj2, { customMerge });
console.log(result); // { a: [1, 2, 3, 4, 5], b: { c: 2, d: 3 } }

Other packages similar to deepmerge-ts

deepmerge

The deepmerge package is a popular library for deep merging objects in JavaScript. It is similar to deepmerge-ts but does not provide TypeScript type safety out of the box.

lodash.merge

Lodash is a utility library that offers a wide range of functions, including deep merging with lodash.merge. While it is versatile and widely used, it is a larger library compared to deepmerge-ts, which is more specialized.

merge-deep

The merge-deep package is another library for deep merging objects. It is simpler and less feature-rich compared to deepmerge-ts, focusing solely on deep merging without additional customization options.

README

DeepmergeTS

Deeply merge 2 or more objects respecting type information.

Installation

Node

# Install with npm
npm install deepmerge-ts --save-dev

# Install with yarn
yarn add -D deepmerge-ts

Features

• Merged output has correct typing.
• Record merging support.
• Array merging support.
• Map and Set merging support.

Usage

Example

import { deepmerge } from "deepmerge-ts";

const x = {
  record: {
    prop1: "value1",
    prop2: "value2",
  },
  array: [1, 2, 3],
  set: new Set([1, 2, 3]),
  map: new Map([
    ["key1", "value1"],
    ["key2", "value2"],
  ]),
};

const y = {
  record: {
    prop1: "changed",
    prop3: "value3",
  },
  array: [2, 3, 4],
  set: new Set([2, 3, 4]),
  map: new Map([
    ["key2", "changed"],
    ["key3", "value3"],
  ]),
};

const output = {
  record: {
    prop1: "changed",
    prop2: "value2",
    prop3: "value3",
  },
  array: [1, 2, 3, 2, 3, 4],
  set: new Set([1, 2, 3, 4]),
  map: new Map([
    ["key1", "value1"],
    ["key2", "changed"],
    ["key3", "value3"],
  ]),
};

deepmerge(x, y) // => output