Benchmark: Lodash merge vs lodash assign

HTML Preparation code:

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

Tests:

MERGE
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = _.merge(a, b);
ASSIGN
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = _.assign(a, b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
MERGE
ASSIGN

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**What is tested?**

The provided JSON represents a JavaScript microbenchmark that compares two functions: `_.merge` and `_.assign`. The test cases involve creating objects, merging or assigning one object to another, and measuring the performance differences between these two approaches.

**Options compared**

The benchmark compares two options:

1. **Lodash merge**: The `_merge` function from the Lodash library merges two objects into a new object.
2. **Lodash assign**: The `_assign` function from the Lodash library copies all enumerable own properties from one object to another, resulting in a new object.

**Pros and cons of each approach**

* **Lodash merge (MERGE)**:
	+ Pros: This approach can be more explicit and easier to read, as it creates a new object with merged properties.
	+ Cons: It might incur overhead due to the creation of a new object.
* **Lodash assign (ASSIGN)**:
	+ Pros: This approach is often faster, as it only copies existing properties from one object to another, without creating a new object.
	+ Cons: It can be less explicit and more concise, making it harder to read for those not familiar with this syntax.

**Other considerations**

When choosing between `_.merge` and `_.assign`, consider the specific use case:

* If you need to merge two objects with similar structures, using `_merge` might be a better choice. However, if you're only copying existing properties from one object to another without changing their structure, `_.assign` could be more efficient.
* Be aware that some browsers may optimize or cache Lodash functions, which can affect benchmark results.

**Library and syntax**

The test case uses the Lodash library, a popular utility library for functional programming in JavaScript. `_merge` and `_assign` are two of its most commonly used functions.

**Special JS features/syntax**

This benchmark does not use any special JavaScript features or syntax that might impact performance or interpretation. The code is straightforward and follows standard JavaScript object creation and property assignment syntax.

**Other alternatives**

If you're interested in exploring alternative approaches, consider:

* **Object.assign()**: This built-in method can be used to assign properties from one object to another.
* **`.concat()`**: In older versions of JavaScript (before ES6), you could use the `.concat()` method to merge objects. However, this approach is generally considered less efficient than `_.merge` or `_.assign`.
* **Manual merging/assignment**: You can also write your own custom function for merging or assigning objects using loops and property accessors.

Keep in mind that benchmarking JavaScript performance involves considering many factors beyond just the code itself, such as browser optimizations, caching, and memory allocation. Always consult the specific documentation for your target browsers to ensure you're optimizing for their unique behavior.

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36

Browser/OS: Chrome 70 on Linux

View result in a separate tab

Test name	Executions per second
MERGE	1985839.8 Ops/sec
ASSIGN	2771342.5 Ops/sec

Related benchmarks:

Lodash merge vs lodash assign (version: 0)

Comparing performance of: MERGE vs ASSIGN

Created: 5 years ago by: Guest

Jump to the latest result

MERGE

ASSIGN

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):