Benchmark: JavaScript spread operator vs Object.assign performance - new objects

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

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

LLMs can make mistakes. Check important info.

Let's break down the JavaScript microbenchmark on MeasureThat.net.

**What is tested:**
The benchmark measures the performance difference between two methods of merging objects in JavaScript:

1. **Spread operator (`...`)**: This method uses the spread operator to create a new object by copying properties from an existing object.
2. **Object.assign()**: This method creates a shallow copy of one or more source objects, merging their properties into a target object.

**Options compared:**
The benchmark compares two options:

1. Using the spread operator (`...`)
2. Using Object.assign()

**Pros and Cons:**

* **Using the spread operator (`...`)**:
	+ Pros:
		- More concise and readable code
		- Faster execution (in this benchmark, Chrome 117)
	+ Cons:
		- Only works with objects that support spread syntax
		- May be slower for very large datasets due to object creation overhead
* **Using Object.assign()**:
	+ Pros:
		- Works with any JavaScript object, including arrays and functions
		- Can handle more complex merging scenarios (e.g., nested objects)
	+ Cons:
		- More verbose code
		- May be slower due to the creation of a new object

**Library usage:**
None of the test cases use any external libraries.

**Special JS features or syntax:**
The benchmark uses the spread operator (`...`), which is a modern JavaScript feature introduced in ECMAScript 2018. It's not compatible with older browsers or versions of JavaScript that don't support it.

**Other considerations:**

* The benchmark measures the performance of creating new objects using both methods.
* The test cases use simple object literals to represent the data being merged, which may not accurately reflect real-world scenarios where data is more complex.
* The benchmark only runs on a desktop platform and Chrome 117 browser, which may limit its generalizability.

**Alternatives:**

* Other methods for merging objects in JavaScript include:
	+ `Object.create()`
	+ `Object.keys()` and `Object.assign()`
	+ Library functions like Lodash's `merge()` or Ramda's `merge`

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36

Browser/OS: Chrome 117 on Windows

View result in a separate tab

Test name	Executions per second
Using the spread operator	47460424.0 Ops/sec
Using Object.assign	11803526.0 Ops/sec

Related benchmarks:

JavaScript spread operator vs Object.assign performance - new objects (version: 0)

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

Created: one year 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 one month ago):