Benchmark: testspeed - MeasureThat.net

Tests:

11
let arr = [1, 2, 3, 4, 5]; arr.forEach((num, index) => { return arr[index] = num * 2; });
33
let arr = [1, 2, 3, 4, 5]; arr.map(num => { return num * 2; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
11
33

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to help explain the provided JavaScript benchmark and its options.

**Overview**

The website MeasureThat.net allows users to create and run JavaScript microbenchmarks to compare the performance of different approaches. The benchmarking framework provides various ways to measure execution time, and the user can choose from different libraries, syntax features, and optimization techniques.

**Benchmark Definition JSON**

The provided Benchmark Definition JSON represents a simple benchmark with two test cases:
```json
{
    "Name": "testspeed",
    "Description": "jsspeed",
    "Script Preparation Code": null,
    "Html Preparation Code": null
}
```
This definition specifies the name, description, and preparation code (none) for the benchmark.

**Individual Test Cases**

There are two individual test cases:
```json
[
    {
        "Benchmark Definition": "let arr = [1, 2, 3, 4, 5];\r\narr.forEach((num, index) => {\r\n    return arr[index] = num * 2;\r\n});",
        "Test Name": "11"
    },
    {
        "Benchmark Definition": "let arr = [1, 2, 3, 4, 5];\r\narr.map(num => {\r\n    return num * 2;\r\n});",
        "Test Name": "33"
    }
]
```
These test cases define two simple JavaScript benchmarks:

1. `11`: The first benchmark uses the `forEach` method to iterate over an array and multiply each element by 2.
2. `33`: The second benchmark uses the `map` method to create a new array with the same elements multiplied by 2.

**Library Used**

In both test cases, no specific library is used beyond the built-in JavaScript methods (`forEach`, `map`). However, in real-world scenarios, libraries like Lodash or Ramda might be used for similar operations.

**Special JS Feature/Syntax**

No special JavaScript features or syntax are mentioned in these benchmarks. The use of ES6-style arrow functions and template literals is common in modern JavaScript code but is not specific to this benchmark.

**Pros and Cons of Different Approaches**

For the `forEach` method:
```json
let arr = [1, 2, 3, 4, 5];
arr.forEach((num, index) => {
    return arr[index] = num * 2;
});
```
Pros:

* Simple to understand and implement
* Works with most browsers

Cons:

* Can be slower due to the use of `return` statements inside the callback function
* May not perform as well for large datasets

For the `map` method:
```json
let arr = [1, 2, 3, 4, 5];
arr.map(num => {
    return num * 2;
});
```
Pros:

* Can be faster than `forEach` due to the lazy evaluation of the mapped values
* Works with most browsers

Cons:

* May require additional memory allocation for large datasets
* Returns a new array, which can affect performance in certain scenarios

**Other Alternatives**

Other alternatives to these approaches include using loops or utilizing more efficient algorithms like parallel processing. Some libraries, like `p-map` or `async-parallel`, provide parallelized versions of the `map` method.

For example, you could use `p-map` to run the `map` operation in parallel:
```javascript
const pMap = require('p-map');

let arr = [1, 2, 3, 4, 5];
arr.map(num => num * 2).then(results => console.log(results));
```
Keep in mind that this approach requires additional libraries and may have different performance characteristics compared to the original `map` method.

In summary, the provided benchmark compares two simple JavaScript approaches for multiplying an array by a factor of 2 using both `forEach` and `map`. While there are pros and cons to each approach, understanding these differences can help developers optimize their code for better performance.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.61 Safari/537.36

Browser/OS: Chrome 94 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
11	37134272.0 Ops/sec
33	12325430.0 Ops/sec

Related benchmarks:

testspeed (version: 0)

jsspeed

Comparing performance of: 11 vs 33

Created: 3 years ago by: Guest

Jump to the latest result

11

33

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):