Benchmark: JavaScript spread operator vs Object.assign performance 21

Tests:

Using the spread operator 22
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign 22
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, firstObject, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator 22
Using Object.assign 22

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36

Browser/OS: Chrome 107 on Windows

View result in a separate tab

Test name	Executions per second
Using the spread operator 22	3076540.5 Ops/sec
Using Object.assign 22	6727593.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down what's being tested in the provided JSON benchmark.

**Benchmark Definition**

The benchmark is designed to compare the performance of two approaches: using the JavaScript spread operator (`...`) and `Object.assign()` to merge two objects into one.

**Options Compared**

1. **Using the Spread Operator (`...`)**:
	* Pros:
		+ Concise and expressive syntax.
		+ Can be faster for small objects due to its optimized implementation in modern browsers and Node.js engines.
	* Cons:
		+ May not perform as well on very large objects, as it involves creating a new array of properties.
2. **Using `Object.assign()`**:
	* Pros:
		+ Well-established and widely supported method for merging objects.
		+ Can handle large objects efficiently by using an optimized implementation in modern browsers and Node.js engines.
	* Cons:
		+ Requires a function call, which can introduce overhead.

**Other Considerations**

* The benchmark likely aims to measure the performance difference between these two approaches on modern JavaScript engines.
* It's essential to note that the spread operator is a relatively recent addition to the JavaScript language (ECMAScript 2018), while `Object.assign()` has been around since ECMAScript 2015. This might affect their performance in different browsers and Node.js versions.

**Library/Extension used**

None mentioned explicitly, but it's likely that the benchmark uses modern JavaScript engines and browsers that support these features without any additional libraries or extensions.

**Special JS Features/Syntax**

The spread operator (`...`) is a relatively new feature introduced in ECMAScript 2018. It allows object spreading in expressions using the syntax `...object`. This feature has been adopted by most modern browsers and Node.js engines, but its support might vary across different environments.

Now, let's look at other alternatives for merging objects:

1. **Object.create()**: This method can be used to create a new object with the specified prototype chain. It's less concise than `Object.assign()` or the spread operator.
2. **Array.prototype.reduce()**: By using `Array.prototype.reduce()` and creating an array of properties, you can merge two objects together. However, this approach is generally less efficient and more verbose than using the spread operator or `Object.assign()`.
3. **Manual property assignment**: You could manually assign properties from one object to another using dot notation (`obj.target.property = obj.source.property`). This method is the most verbose and potentially error-prone of the three options.

Keep in mind that these alternatives might not be as efficient or concise as the spread operator or `Object.assign()`, which are optimized for performance and readability.

Related benchmarks:

JavaScript spread operator vs Object.assign performance 21 (version: 0)

Comparing performance of: Using the spread operator 22 vs Using Object.assign 22

Created: 3 years ago by: Guest

Jump to the latest result

Using the spread operator 22

Using Object.assign 22

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):