Benchmark: lodash merge vs deepmerge

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
<script src='https://unpkg.com/deepmerge@3.2.0/dist/umd.js'></script>

Tests:

lodash merge
var a = { a: 'oh', b: 'my', c: { a: 'a', b: { c: 'c' } } }; var b = { c: { b: { d: 'a' }, c: { d: 'd' } } }; var c = _.merge({}, a, b);
object.assign
var a = { a: 'oh', b: 'my', c: { a: 'a', b: { c: 'c' } } }; var b = { c: { b: { d: 'a' }, c: { d: 'd' } } }; var c = deepmerge({}, a, b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash merge
object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:148.0) Gecko/20100101 Firefox/148.0

Browser/OS: Firefox 148 on Windows

View result in a separate tab

Test name	Executions per second
lodash merge	447335.8 Ops/sec
object.assign	1290271.6 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The provided JSON represents two test cases, comparing the performance of three different approaches to merge two objects in JavaScript:

1. `_.merge` from Lodash (a popular utility library)
2. `deepmerge` (a pure object merger library)
3. `object.assign`

These libraries are used to merge objects, which is a common operation in many programming tasks.

**Options compared**

Here's a brief overview of each option:

1. **Lodash _.merge**: This function takes two objects as input and returns a new object that contains all the properties from both objects.
2. **deepmerge**: This library provides a pure object merger, which means it creates a new object without modifying the original objects. It's designed to be fast and efficient.
3. **object.assign**: This is a built-in JavaScript method that takes two or more objects as input and returns a new object containing all the properties from the input objects.

**Pros and Cons of each approach**

1. **Lodash _.merge**:
	* Pros: Easy to use, widely supported, and well-documented.
	* Cons: It creates a new object and may not be suitable for very large objects due to memory constraints.
2. **deepmerge**:
	* Pros: Fast, efficient, and designed specifically for merging objects.
	* Cons: May require additional setup and learning curve compared to Lodash _.merge.
3. **object.assign**:
	* Pros: Built-in method, easy to use, and suitable for most cases.
	* Cons: It can be slower than deepmerge, especially when dealing with large objects.

**Other considerations**

When choosing between these approaches, consider the following factors:

* Performance: If you need to merge very large objects or perform this operation frequently, deepmerge might be a better choice. For smaller objects and less frequent merging, Lodash _.merge or object.assign might suffice.
* Memory usage: Lodash _.merge creates a new object, which can lead to memory issues when dealing with very large objects. object.assign also creates a new object, while deepmerge returns the merged object directly without creating an intermediate result.

**Library description and purpose**

1. **Lodash**: A utility library that provides various functions for tasks like array manipulation, string formatting, and object merging.
2. **deepmerge**: A pure object merger library designed to be fast and efficient when working with objects.

**Special JS feature or syntax**

None mentioned in the provided JSON.

Now, let's discuss some alternative approaches that could have been used:

1. **Recursion**: You can implement a recursive function to merge two objects by iterating through their properties.
2. **Iterative merging**: Similar to recursion, but uses iteration instead of function calls to merge objects.
3. **Use of Map or reduce**: Some libraries like Ramda provide functions that use maps or reductions to merge objects.

Keep in mind that these alternatives might not be as efficient or concise as the options compared, and may require more boilerplate code.

Related benchmarks:

lodash merge vs deepmerge (version: 0)

Comparing performance of: lodash merge vs object.assign

Created: 6 years ago by: Guest

Jump to the latest result

lodash merge

object.assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):