Benchmark: Spread vs Object.assign vs forEach

Tests:

Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign(firstObject, secondObject); finalObject['sampleData'] == 'Hello world';
Not merging
const firstObject = [{ sampleData: 'Hello world' }, {sampleData: 'Hello world'}] firstObject.forEach(key => {firstObject['sampleData'] == 'Hello world'; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using Object.assign
Not merging

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/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36

Browser/OS: Chrome 109 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using Object.assign	5440219.0 Ops/sec
Not merging	132690936.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided benchmark measures the performance of three different approaches to merge objects in JavaScript:

1. **`Object.assign()`**: This is a built-in method that merges one or more source objects into a target object. It takes an optional array of sources, which are merged into the target object.
2. **`forEach()` loop with assignment**: In this approach, the `forEach()` method is used to iterate over the properties of the first object, and for each property, it assigns its value to the corresponding property in the second object.

**Options Comparison**

The two main options being compared are:

* `Object.assign()`: This is a built-in method that merges objects. It's a simple and efficient way to merge objects.
* `forEach()` loop with assignment: This approach uses an array of properties from the first object and iterates over them using `forEach()`. For each property, it assigns its value to the corresponding property in the second object.

**Pros and Cons**

* **`Object.assign()`**:
	+ Pros:
		- Fast and efficient
		- Built-in method, which means it's optimized for performance
		- Easy to use
	+ Cons:
		- Only works with objects that have enumerable properties
		- Can be slower than other approaches if the source object is large
* **`forEach()` loop with assignment**:
	+ Pros:
		- Works with any type of iterable (arrays, maps, etc.)
		- Can be faster than `Object.assign()` for very large objects
	+ Cons:
		- Requires an extra iteration over the properties, which can slow down performance
		- Less intuitive to use

**Library and Special JS Features**

* **`Object.assign()`**: This is a built-in method in JavaScript, so no library or special feature is required.
* **No special JS features are used in this benchmark**, except for the `forEach()` method, which is a standard part of JavaScript.

**Other Alternatives**

If you need to merge objects with more complex logic (e.g., merging arrays with different types), other alternatives might include:

* Using a library like Lodash's `merge()` function
* Using a custom implementation that uses `Object.keys()` and `reduce()`
* Using a framework or library like React's `combineLatest` function

Keep in mind that the best approach will depend on your specific use case and requirements.

Related benchmarks:

Spread vs Object.assign vs forEach (version: 0)

Comparing performance of: Using Object.assign vs Not merging

Created: one year ago by: Guest

Jump to the latest result

Using Object.assign

Not merging

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):