Benchmark: JavaScript reduce vs Object.assign performance

Tests:

Using reduce
const firstObject = { '...': true } const arrayOfObjects = [{ moreData: 'foo bar' }, { evenMore: 'data' }] const finalObject = arrayOfObjects.reduce((result, object) => ({ ...result, ...object }), { '...': true })
Using Object.assign
const firstObject = { '...': true } const arrayOfObjects = [{ moreData: 'foo bar' }, { evenMore: 'data' }] const finalObject = Object.assign(firstObject, ...arrayOfObjects);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using reduce
Using Object.assign

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/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using reduce	16992730.0 Ops/sec
Using Object.assign	24893022.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the JavaScript benchmarking test.

**What is being tested?**

The provided JSON represents two individual test cases that compare the performance of `Array.prototype.reduce()` and `Object.assign()`. Both tests involve creating an initial object, adding multiple objects to it using one of these methods, and measuring their execution times.

**Options compared:**

1. **Using reduce**: This method iterates over the array of objects, applying a reduction function to each object in turn, accumulating the results into a new object.
2. **Using Object.assign()**: This method creates a shallow copy of an existing object (in this case, `firstObject`) and then merges the properties of subsequent arrays (`arrayOfObjects`) into it.

**Pros and Cons:**

* **Using reduce**:
	+ Pros:
		- More flexible, as it allows for custom reduction functions.
		- Can handle more complex data structures.
	+ Cons:
		- May have higher overhead due to the iteration process.
		- Can be slower for large datasets.
* **Using Object.assign()**:
	+ Pros:
		- Faster and more efficient for simple object merging.
		- Less overhead, as it leverages existing JavaScript optimizations.
	+ Cons:
		- Limited flexibility, as it only supports shallow copying and merging.
		- Can lead to performance issues when dealing with large datasets or deeply nested objects.

**Libraries and special features:**

Neither of these test cases uses any external libraries. However, if we were to consider the broader context of JavaScript development, `Object.assign()` has been a part of the language since ECMAScript 2015 (ES6).

**Special syntax:**

The reduction function in the `Using reduce` test case uses an arrow function (`(result, object) => ({ ...result, ...object })`). This is a modern syntax feature introduced in ECMAScript 2015 (ES6), which allows for concise and expressive functions.

**Other alternatives:**

If you're interested in exploring alternative approaches, consider:

* Using `Array.prototype.forEach()` or `for...of` loops to iterate over the array of objects.
* Implementing a custom merging function using JavaScript's built-in `Object.keys()`, `Object.values()`, and `reduce()` methods.
* Utilizing libraries like Lodash (which provides a `merge()` function) or Ramda (which offers an `object.merge()` function).

Keep in mind that each alternative will have its own trade-offs in terms of performance, readability, and maintainability.

Related benchmarks:

JavaScript reduce vs Object.assign performance (version: 0)

Comparing performance of: Using reduce vs Using Object.assign

Created: 4 years ago by: Guest

Jump to the latest result

Using reduce

Using Object.assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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