Benchmark: Array.prototype.concat vs spread operator

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

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36

Browser/OS: Chrome 66 on Linux

View result in a separate tab

Test name	Executions per second
lodash merge	1496102.5 Ops/sec
object.assign	2124601.2 Ops/sec
spread	1742482.2 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months 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 a benchmark test that compares three different approaches to merge two objects:

1. **`Object.assign()`**: a traditional method for merging objects.
2. **Spread operator (`...`)**: a new ES6 feature introduced in 2015, which allows you to merge objects by spreading their properties into another object.
3. **Lodash's `merge()` function**: a utility function from the popular JavaScript library Lodash.

**Options being compared**

The benchmark tests these three approaches on a simple example: merging two objects `{ a: 'oh', b: 'my' }` and `{ c: 'goddess' }`. The goal is to determine which approach is faster, more efficient, or has fewer side effects.

**Pros and cons of each approach**

1. **`Object.assign()`**:
	* Pros: widely supported, simple syntax.
	* Cons: can be slower than other approaches, creates a new object with a shallow copy of the merged properties.
2. **Spread operator (`...`)**:
	* Pros: concise syntax, efficient merging of objects, and minimal overhead.
	* Cons: introduced in ES6, so older browsers might not support it.
3. **Lodash's `merge()` function**:
	* Pros: well-tested, reliable implementation, supports more advanced merging scenarios (e.g., nested objects).
	* Cons: adds an external dependency, requires a library installation.

**Library usage**

The benchmark includes Lodash's `merge()` function as one of the test cases. Lodash is a popular JavaScript utility library that provides a wide range of functions for tasks like string manipulation, array manipulation, and object manipulation (in this case, merging objects).

**Special JS feature**

There are no special features mentioned in the provided JSON, but it's worth noting that newer browsers and engines have better support for modern JavaScript features, such as ES6 classes, async/await, and more.

**Other alternatives**

If you want to explore other approaches or alternatives, here are a few examples:

* **`Array.prototype.reduce()`**: another way to merge objects by iteratively accumulating properties.
* **`JSON.parse(JSON.stringify(obj))`**: using JSON parsing to create a deep copy of an object, then merging with another object.
* **Custom implementation**: you can write your own function to merge objects using a specific algorithm or data structure.

Keep in mind that each approach has its trade-offs and use cases. The benchmark helps determine the best approach for a particular scenario, but it's essential to consider the context and requirements of your project when choosing an implementation method.

Related benchmarks:

Array.prototype.concat vs spread operator (version: 0)

Compare the new ES6 spread operator with the traditional concat() method

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

Created: 6 years ago by: Guest

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 2 months ago):