Benchmark: JavaScript spread operator vs Object.assign performance (empty)

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

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/98.0.4758.102 Safari/537.36

Browser/OS: Chrome 98 on Windows

View result in a separate tab

Test name	Executions per second
Using the spread operator	54205956.0 Ops/sec
Using Object.assign	3049310.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this JavaScript microbenchmark.

**Benchmark Overview**

The benchmark is comparing the performance of two approaches for creating a shallow copy of an object:

1. Using the spread operator (`...`)
2. Using `Object.assign()` with an empty object as the target.

**What are we comparing?**

We're comparing the execution time and speed of these two approaches on a desktop Windows machine running Chrome 98.

**Options Compared:**

* Spread Operator (`const finalObject = { ...firstObject }`)
* `Object.assign()`: Creating a shallow copy using this method.

**Pros and Cons of Each Approach:**

1. **Spread Operator (`...`):**
	* Pros:
		+ More concise and readable code.
		+ Less error-prone, as it's harder to make mistakes with the syntax.
	* Cons:
		+ May not work correctly if the original object has non-enumerable properties or is a complex data structure (e.g., array-like objects).
2. `Object.assign():`
	* Pros:
		+ Works correctly even if the original object has non-enumerable properties or is a complex data structure.
	* Cons:
		+ Less concise and more verbose code, making it less readable.
		+ More error-prone due to the need for precise syntax.

**Library Usage:**

None of the provided benchmark definitions use any external libraries. However, it's worth noting that `Object.assign()` is a built-in method in JavaScript, while the spread operator (`...`) is supported since ECMAScript 2018.

**Special JS Features or Syntax:**

The benchmark uses ES6 syntax for the spread operator (`...`), which was introduced in ECMAScript 2015. This feature allows for more concise and readable object creation.

**Other Considerations:**

When deciding between these two approaches, consider the following:

* If you need a shallow copy of an object with a simple structure, the spread operator might be a better choice due to its readability and conciseness.
* If you need to create a copy of a complex data structure or an object with non-enumerable properties, `Object.assign()` is likely a safer option.

**Other Alternatives:**

If you're looking for alternative approaches to creating copies of objects in JavaScript:

1. **`JSON.parse(JSON.stringify(obj))`:** This method creates a deep copy of an object, but it's not recommended due to potential security issues and performance overhead.
2. `Array.prototype.slice()` or `Array.prototype.concat()`: These methods create shallow copies of arrays.

Keep in mind that the best approach depends on your specific use case and requirements. Always consider readability, maintainability, and performance when choosing a solution.

Related benchmarks:

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

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

Created: 2 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

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):