Benchmark: JavaScript spread operator vs Object.assign performance eric

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: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.190 Safari/537.36

Browser/OS: Chrome 88 on Windows

View result in a separate tab

Test name	Executions per second
Using the spread operator	1205029.6 Ops/sec
Using Object.assign	2657753.2 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.

**Benchmark Definition**

The benchmark is designed to compare the performance of two ways to merge objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. The script preparation code is empty, which means the benchmark is focused on comparing the execution time of these two approaches.

**Test Cases**

There are two test cases:

1. **Using the spread operator**: This test case uses the spread operator to merge two objects, `firstObject` and `secondObject`, into a single object `finalObject`. The syntax is: `{...firstObject,...secondObject}`.
2. **Using Object.assign()**: This test case uses the `Object.assign()` method to merge two objects, `firstObject` and `secondObject`, into a single object `finalObject`. The syntax is: `Object.assign({}, firstObject, secondObject)`.

**Pros and Cons**

* **Using the spread operator (`...`)**:
	+ Pros: Concise and readable syntax. No need to specify multiple arguments for `Object.assign()`.
	+ Cons: May be slower due to the creation of a new object with the spread operator.
* **Using Object.assign()**:
	+ Pros: Can handle arbitrary objects as arguments, including nested objects.
	+ Cons: Requires specifying multiple arguments, which can make the code more verbose.

**Other Considerations**

Both approaches have their trade-offs. The spread operator is often preferred for its readability and conciseness, but it may incur a small performance overhead due to object creation. `Object.assign()` is more flexible, but its verbosity can make the code harder to read.

**Library Usage**

There is no explicit library usage in this benchmark. However, if you were to add libraries, some potential options could be:

* Lodash: Provides utility functions like `merge` or `pick`, which might be used to merge objects.
* Ramda: Offers a range of functional programming utilities, including `fromPairs` and `merge`, for working with objects.

**Special JS Features/Syntax**

This benchmark does not use any special JavaScript features or syntax. It only focuses on comparing the performance of two basic object merging approaches.

**Alternatives**

If you were to create similar benchmarks, some alternative test cases could be:

* Using destructuring assignment (`{...firstObject, ...secondObject}`)
* Using `reduce()` and accumulating objects
* Using a custom function or utility library for merging objects

Related benchmarks:

JavaScript spread operator vs Object.assign performance eric (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):