Benchmark: xxx vs xxx2 - MeasureThat.net

Script Preparation code:

var arr = Array(10_000).fill(0)

Tests:

1
arr.reduce((acc, x) => acc.concat(x, x), []);
2
arr.flatMap(x => [x, x])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
1
2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
1	3.6 Ops/sec
2	711.1 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 provided benchmark and explain what's being tested.

**Benchmark Definition**

The website MeasureThat.net allows users to create and run JavaScript microbenchmarks. The provided JSON represents a benchmark definition, which consists of two parts:

1. **Script Preparation Code**: This is a snippet of JavaScript code that is executed before running each test case. In this case, it initializes an array `arr` with 10,000 zeros using the `Array.fill()` method.

```javascript
var arr = Array(10_000).fill(0);
```

The purpose of this script is to set up a large array for testing, which will be used in both test cases.

2. **Html Preparation Code**: This is another snippet of JavaScript code that is executed before running each test case. However, the `Html Preparation Code` field is empty (`null`) in this example.

**Individual Test Cases**

The benchmark definition includes two individual test cases:

1. `arr.reduce((acc, x) => acc.concat(x, x), [])`
2. `arr.flatMap(x => [x, x])`

These test cases measure the performance of different array methods: `reduce()` and `flatMap()`, respectively.

**Pros and Cons of Different Approaches**

When it comes to benchmarking JavaScript array methods, there are a few approaches to consider:

1. **Native Methods vs. polyfills**: MeasureThat.net uses native methods (i.e., built-in JavaScript functions) for the tests. However, some browsers may not support these methods natively. In such cases, using polyfills can ensure compatibility.
2. **Array size and type**: The benchmarked array size is quite large (10,000 elements). This could affect performance, especially if the system resources are limited. Using smaller arrays might provide more accurate results.
3. **Browser differences**: The tests are run in different browsers (in this case, Chrome 119 on Windows). This means that the results may vary between browsers due to their implementation of JavaScript features.

**Libraries and Special JS Features**

There are no external libraries used in these test cases. However, it's worth noting that some modern JavaScript engines might employ various optimization techniques or feature flags that could affect performance.

**Special JS Feature:**

* `flatMap()` is a relatively new method introduced in ECMAScript 2019 (ES2020). It's designed to simplify the iteration over an array and create a new array with transformed values. While it's not universally supported, most modern browsers support it.
* `reduce()` has been a part of JavaScript for a long time but is still widely used.

**Other Alternatives**

If you wanted to benchmark similar operations using other methods or libraries, you could consider the following:

1. **Array iteration**: Use traditional `for` loops instead of `reduce()` and `flatMap()`.
2. **Polyfills**: Implement polyfills for newer JavaScript features, like `flatMap()`, in older browsers.
3. **Third-party libraries**: Utilize libraries like Lodash or Ramda to implement these array methods, which might provide additional performance benefits or more flexible implementations.

Keep in mind that using alternative approaches might change the focus of your benchmarking efforts and may not directly compare with MeasureThat.net's results.

I hope this explanation helps software engineers understand what's being tested in this benchmark!

Related benchmarks:

xxx vs xxx2 (version: 0)

Comparing performance of: 1 vs 2

Created: 2 years ago by: Guest

Jump to the latest result

1

2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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