Benchmark: v2 JavaScript spread operator vs Object.assign performance

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using Object.assign
using spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.5 Safari/605.1.15

Browser/OS: Safari 16 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using Object.assign	2961524.0 Ops/sec
using spread	6482488.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, the options compared, their pros and cons, and other considerations.

**What is being tested?**

The benchmark compares the performance of two ways to merge objects in JavaScript: using `Object.assign()` and using the spread operator (`...`).

**Options compared:**

1. **Using `Object.assign()`:**
	* This method takes multiple arguments with object values, merging them into a new object.
	* Example usage: `const finalObject = Object.assign({}, firstObject, secondObject);`
2. **Using the spread operator (`...`):**
	* This method uses syntax like `{ ...firstObject, ...secondObject }` to create a new object with merged properties.
	* Example usage: `const finalObject = {...firstObject, ...secondObject};`

**Pros and Cons of each approach:**

1. **Using `Object.assign()`:**
	* Pros:
		+ Supports merging multiple objects into one.
		+ Can be used with arrays and other types of objects.
	* Cons:
		+ Requires specifying the initial object (`{}`).
		+ May have performance overhead due to method calls.
2. **Using the spread operator (`...`):**
	* Pros:
		+ More concise syntax, reducing code duplication.
		+ Faster execution since it's just syntactic sugar.
	* Cons:
		+ Limited to merging objects; not compatible with all data types.

**Library usage:**

The benchmark uses `Object.assign()` and the spread operator (`...`), which are built-in JavaScript features. No external libraries are required for this comparison.

**Special JS feature or syntax:**

The use of the spread operator (`...`) is a modern JavaScript feature introduced in ECMAScript 2018. It allows for more concise object merging, making it easier to write code that doesn't require explicit method calls.

**Other alternatives:**

If you wanted to merge objects differently, you could also consider using:

1. `concat()`: Merges two or more arrays into one, but can be slower and less efficient.
2. Loops: You could use a loop to iterate over the properties of each object and add them to a new object.

However, these alternatives are not used in this benchmark, as the focus is specifically on comparing `Object.assign()` and the spread operator (`...`).

I hope this explanation helps! Let me know if you have any further questions.

Related benchmarks:

v2 JavaScript spread operator vs Object.assign performance (version: 0)

Comparing performance of: Using Object.assign vs using spread

Created: one year ago by: Guest

Jump to the latest result

Using Object.assign

using 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):