Benchmark: lodash merge vs deepmerge vs Object.assign

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);
deepmerge
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);
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 = Object.assign({}, a, b);

Historical Performance Data aggregated from 13 community runs

Desktop Results:

Chrome 13 runs

object.assign

17.3M/s

deepmerge

3.6M/s

lodash merge

616K/s

Fastest: object.assign (28.1x faster)

View exact numbers

✓ object.assign: 17,295,632 ops/sec
• deepmerge: 3,602,062 ops/sec
• lodash merge: 615,908 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash merge
deepmerge
object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 15 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36

Browser/OS: Chrome 150 on Mac OS X 10.15.7

View result in a separate tab

object.assign

31.1M/s

deepmerge

5.1M/s

lodash merge

865K/s

View exact numbers

Test name	Executions per second
✓ object.assign	31,071,624 Ops/sec
deepmerge	5,069,032 Ops/sec
lodash merge	865,007 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and the pros and cons of each approach.

**Overview**
The benchmark is designed to compare the performance of three functions:

1. `Object.assign()`
2. `deepmerge()`
3. `lodash.merge()`

These functions are used to merge two objects into one. The test cases use similar input data with slight variations, allowing us to isolate the differences in performance between these libraries.

**What's being tested**

The benchmark is testing how efficient each library is when merging objects. Specifically, it's measuring:

* How many executions per second (executionsPerSecond) for each library
* The speed difference between the three libraries

**Options compared**

1. **`Object.assign()`**: A built-in JavaScript function that merges two or more source objects into a new object.
2. **`deepmerge()`**: A third-party library that provides a deep merge function, allowing you to merge objects recursively.
3. **`lodash.merge()`**: A utility function from the Lodash library that performs a deep merge of two objects.

**Pros and Cons**

1. `Object.assign()`:
	* Pros: Built-in, easy to use, no dependencies.
	* Cons: Can lead to shallow merges if not used carefully, performance might be slower than specialized libraries.
2. `deepmerge()`:
	* Pros: Efficient for deep merges, handles recursive structures well, and is a dedicated library for this purpose.
	* Cons: Requires additional dependency (the library itself), might have a steeper learning curve due to its specific API.
3. `lodash.merge()`:
	* Pros: Fast, reliable, and easy to use within the context of Lodash, which provides many other useful utility functions.
	* Cons: Adds an extra dependency (Lodash) and might not be as efficient as dedicated libraries like `deepmerge()`.

**Library explanations**

1. `deepmerge`: A small library created by Andrew Whitehurst that provides a simple and efficient way to merge objects recursively. It's designed for use cases where deep merging is necessary, such as when working with complex data structures.
2. `lodash.merge()`: A part of the Lodash utility library, which includes many functions for common tasks like array manipulation, object creation, and more. The `merge()` function is specifically designed to handle deep merges of objects.

**Special JS features or syntax**

None are mentioned in this benchmark.

lodash merge vs deepmerge vs Object.assign (version: 0)

Comparing performance of: `lodash merge vs deepmerge vs object.assign`

Created: 4 years ago by: Guest

Go to the latest result

lodash merge

deepmerge

object.assign

Historical Performance Data aggregated from 13 community runs

Desktop Results:

Chrome 13 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

lodash merge vs deepmerge vs Object.assign (version: 0)

Comparing performance of: lodash merge vs deepmerge vs object.assign

Created: 4 years ago by: Guest

Go to the latest result

lodash merge

deepmerge

object.assign

Historical Performance Data aggregated from 13 community runs

Desktop Results:

Chrome 13 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `lodash merge vs deepmerge vs object.assign`