Benchmark: lodash merge vs object.assign vs spread v2222

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Tests:

lodash merge
var a = { "index": 1, "index_start_at": 56, "integer": 38, "float": 17.9152, "name": "Jim", "surname": "Cherry", "fullname": "Jennifer McLean", "email": "dan@crane.et", "bool": false } var b = { "index": 2, "index_start_at": 57, "integer": 4, "float": 19.2675, "name": "Sue", "surname": "Houston", "fullname": "Ralph Bolton", "email": "glenda@walton.fr", "bool": false } var c = _.merge(a, b);
object.assign
var a = { "index": 1, "index_start_at": 56, "integer": 38, "float": 17.9152, "name": "Jim", "surname": "Cherry", "fullname": "Jennifer McLean", "email": "dan@crane.et", "bool": false } var b = { "index": 2, "index_start_at": 57, "integer": 4, "float": 19.2675, "name": "Sue", "surname": "Houston", "fullname": "Ralph Bolton", "email": "glenda@walton.fr", "bool": false } var c = Object.assign(a, b);
spread
var a = { "index": 1, "index_start_at": 56, "integer": 38, "float": 17.9152, "name": "Jim", "surname": "Cherry", "fullname": "Jennifer McLean", "email": "dan@crane.et", "bool": false } var b = { "index": 2, "index_start_at": 57, "integer": 4, "float": 19.2675, "name": "Sue", "surname": "Houston", "fullname": "Ralph Bolton", "email": "glenda@walton.fr", "bool": false } var c = { ...a, ...b };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash merge
object.assign
spread

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**What is being tested?**

The provided benchmark tests three approaches for merging two objects:

1. `_.merge` (from the Lodash library)
2. `Object.assign`
3. Spread operator (`...`)

These approaches are compared to determine which one performs best in terms of execution speed.

**Options comparison:**

Here's a brief overview of each approach:

* **_.merge**: This function from Lodash takes two objects as input and returns a new object with the merged properties.
	+ Pros: Well-tested, widely supported, and provides more control over the merge process.
	+ Cons: Additional dependency on Lodash, might be slower due to the overhead of the library.
* **Object.assign**: This method returns a new object with the assigned values from another object.
	+ Pros: Built-in JavaScript method, fast, and widely supported.
	+ Cons: Can lead to unexpected behavior if not used carefully (e.g., overwriting existing properties).
* **Spread operator (`...`)**: This syntax creates a new object with spreadable properties from an existing object(s).
	+ Pros: Fast, simple, and concise. No additional dependencies required.
	+ Cons: Limited control over the merge process, might not work as expected if objects have different property types.

**Other considerations:**

* **Libraries**: The `_.merge` function uses a variety of algorithms to handle different cases (e.g., arrays, null, undefined). While this provides more flexibility, it also introduces additional overhead.
* **Browser differences**: The benchmark results show variations in execution speed across different browsers and devices. This highlights the importance of testing on multiple platforms to ensure accurate results.

**What is the library used?**

The `_.merge` function comes from the Lodash library (version 4.17.5). Lodash is a popular utility library for JavaScript that provides various helper functions, including `merge`.

**Special JS features or syntax:**

There are no specific JavaScript features or syntaxes mentioned in the benchmark definition. However, it's worth noting that modern JavaScript versions (ECMAScript 2018 and later) support the spread operator (`...`) as a part of the language.

**Alternative approaches:**

If you're interested in exploring other options, here are a few alternatives:

* **Recursive merge**: You can implement your own recursive merge function using a simple loop. This approach provides full control over the merge process but might be slower and more error-prone than the built-in methods.
* **JSON merge libraries**: There are dedicated JSON merge libraries available that offer advanced features like merging arrays, objects with different property types, and handling null or undefined values.
* **Simple object copy**: You can also use a simple `Object.assign` chain to create a new object with merged properties. While this approach is concise, it might not provide the best performance or flexibility.

I hope this explanation helps you understand the benchmark!

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36

Browser/OS: Chrome 71 on Mac OS X 10.14.2

View result in a separate tab

Test name	Executions per second
lodash merge	1008974.9 Ops/sec
object.assign	3213906.0 Ops/sec
spread	1250393.6 Ops/sec

Related benchmarks:

lodash merge vs object.assign vs spread v2222 (version: 0)

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

Created: 5 years ago by: Registered User

Jump to the latest result

lodash merge

object.assign

spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):