Benchmark: Fork of JavaScript spread operator vs Object.assign performance

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
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
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 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36

Browser/OS: Chrome 99 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using the spread operator	2471160.2 Ops/sec
Using Object.assign	4971930.0 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 the provided JSON benchmark.

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

**Options Compared**

1. **Using the spread operator**: This method uses the syntax `{ ...firstObject, ...secondObject }` to create a new object that combines properties from both `firstObject` and `secondObject`. The spread operator is a relatively modern feature introduced in ECMAScript 2018 (ES2018).
2. **Using Object.assign()**: This method takes two or more objects as arguments and returns a new object with the merged properties. It's been a part of JavaScript since its inception.

**Pros and Cons**

* **Using the spread operator:**
	+ Pros:
		- More concise and readable syntax.
		- Avoids the need to use `Object.create()` or other workarounds for older browsers.
	+ Cons:
		- May have slightly worse performance due to the overhead of creating a new object and iterating over its properties.
* **Using Object.assign():**
	+ Pros:
		- Well-established and widely supported across different browsers and versions.
		- Can be used with arrays, objects, or other iterables (e.g., `Object.assign([], [1, 2, 3])`).
	+ Cons:
		- Requires more code to achieve the same result (`const finalObject = Object.assign({}, firstObject, secondObject);`).

**Library and Special JS Features**

In this benchmark, there's no mention of using any libraries or special JavaScript features beyond the two merge methods being compared. However, it's worth noting that other libraries like Lodash might provide alternative ways to achieve similar results.

**Test Case Considerations**

The test cases are designed to create simple objects with a few properties and then merge them using both methods. This allows for a straightforward comparison of performance without introducing complex scenarios or edge cases.

**Alternative Approaches**

If you were to rewrite the benchmark to include more alternatives, some options might be:

1. **Using destructuring**: `const finalObject = { ...firstObject, ...secondObject };` is similar to using the spread operator but uses destructuring syntax.
2. **Using Object.create() and assign()**: This method involves creating a new object using `Object.create()` and then assigning properties from both objects using `assign()`. (Example: `const finalObject = Object.create(firstObject).assign(secondObject);`)
3. **Using `for...in` loop and property iteration**: This approach would involve iterating over the properties of both objects using a `for...in` loop and then assigning each property to the new object.

These alternative approaches might provide additional insights into performance differences between merge methods, but they may also introduce more complexity and overhead.

Related benchmarks:

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

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

Created: 3 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):