Benchmark: Spread vs Ramda's mergeLeft

HTML Preparation code:


<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.29.1/ramda.min.js"></script>

Tests:

Spread
var a = { a: 'oh', b: 'my' }; var b = { b: 'my2', c: 'goddess' }; var c = { ...a, ...b };
MergeLeft
var a = { a: 'oh', b: 'my' }; var b = { b: 'my2', c: 'goddess' }; var c = R.mergeLeft(b, a);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread
MergeLeft

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Spread	15611165.0 Ops/sec
MergeLeft	4527933.5 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares the performance of two approaches to merge two objects: the traditional JavaScript spread operator (`...`) and Ramda's `mergeLeft` function. The test creates three objects (`a`, `b`, and `c`) with overlapping properties, then uses each approach to create a new object that combines `a` and `b` (or vice versa).

**Options Compared**

1. **Spread Operator (`...`)**:
	* This is the traditional JavaScript way to merge two objects.
	* It creates a new object by copying all properties from the first object (`a`) and adding any additional properties from the second object (`b`).
	* Pros: Simple, widely supported, and easy to understand.
	* Cons: Can lead to slower performance due to property iteration and creation of a new object.
2. **Ramda's `mergeLeft` function**:
	* This is a functional programming approach to merging two objects.
	* It creates a new object by copying all properties from the first object (`a`) and adding any additional properties from the second object (`b`), while preserving the original property order.
	* Pros: Efficient, as it avoids creating a new object or iterating over properties. It also preserves the original property order.
	* Cons: Requires knowledge of Ramda library and functional programming concepts.

**Other Considerations**

* **Object size**: The benchmark's performance may vary depending on the size of the objects being merged.
* **Property names**: If the property names are unique, the spread operator might be slightly faster due to faster lookup times in JavaScript. However, this is not a guarantee, and Ramda's `mergeLeft` function can still outperform the spread operator for larger object sizes.

**Library: Ramda**

Ramda is a popular functional programming library for JavaScript that provides various utility functions, including `mergeLeft`. The `mergeLeft` function takes two objects as arguments and returns a new object with merged properties, preserving the original property order. This approach can be beneficial when you need to preserve the original structure of one of the objects.

**Special JS Feature: None**

There are no special JavaScript features or syntax used in this benchmark.

**Alternatives**

If you're looking for alternative approaches to merging objects, consider:

1. **Lodash's `merge` function**: Similar to Ramda's `mergeLeft`, but with a different implementation and API.
2. **Object.assign() method**: Another way to merge objects in JavaScript, which is more efficient than the spread operator when dealing with large object sizes.
3. **Immutable.js library**: A popular alternative to traditional object creation and merging, offering a functional programming approach.

Keep in mind that the choice of approach depends on your specific use case, performance requirements, and personal preference.

Related benchmarks:

Spread vs Ramda's mergeLeft (version: 0)

Comparing performance of: Spread vs MergeLeft

Created: 2 years ago by: Guest

Jump to the latest result

Spread

MergeLeft

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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