Benchmark: for vs reverse - MeasureThat.net

Tests:

reverse
function createStars(num) { let result = []; for (let i = 1; i <= num; i++) { result.push(`${"*".repeat(2 * i - 1)}`); } result.push(...result.slice(0, -1).reverse()); return result.join("\n"); } console.log(createStars(3));
for
function createStars(num) { let result = ""; for (let i = 1; i <= num; i++) { result += `${"*".repeat(2 * i - 1)}\n`; } for (let i = num - 1; i > 0; i--) { result += `${"*".repeat(2 * i - 1)}\n`; } return result; } console.log(createStars(3));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reverse
for

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36

Browser/OS: Chrome 148 on Windows

View result in a separate tab

for

339K/s

reverse

325K/s

View exact numbers

Test name	Executions per second
✓ for	338,877 Ops/sec
reverse	325,468 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explore what's being tested in this benchmark.

**Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. In this specific benchmark, we have two test cases: "for" and "reverse". The goal is to compare the performance of these two approaches in creating a string with asterisks (\*) using different methods.

**Benchmark Definition JSON**

The benchmark definition JSON contains information about the benchmark itself:

* `Name`: The name of the benchmark.
* `Description`: A brief description of the benchmark (empty in this case).
* `Script Preparation Code`: No script preparation code is provided, which means that the JavaScript code for each test case will be executed directly without any additional setup or initialization.
* `Html Preparation Code`: Also no html preparation code is provided.

**Individual Test Cases**

There are two individual test cases:

1. **"for"**: This test case uses a traditional for loop to create the string with asterisks. The JavaScript code is:
```javascript
function createStars(num) {
  let result = "";
  for (let i = 1; i <= num; i++) {
    result += `${"*".repeat(2 * i - 1)}\n`;
  }
  return result;
}
console.log(createStars(3));
```
2. **"reverse"**: This test case uses the `slice()` and `reverse()` methods to create the string with asterisks in reverse order. The JavaScript code is:
```javascript
function createStars(num) {
  let result = [];
  for (let i = 1; i <= num; i++) {
    result.push(`${"*".repeat(2 * i - 1)}`);
  }
  result.push(...result.slice(0, -1).reverse());
  return result.join("\n");
}
console.log(createStars(3));
```
**Library and Special JS Features**

In both test cases, we can see that the `slice()` method is used to extract a subset of elements from the `result` array. The `reverse()` method is also used to reverse the order of the elements in the `result` array.

Additionally, the `"for"` test case uses a traditional for loop with an incrementing variable (`i`) to iterate over the range of numbers.

**Pros and Cons**

Here are some pros and cons for each approach:

* **Traditional for loop ("for")**:
	+ Pros: Simple and easy to understand.
	+ Cons: May be slower than other approaches due to the overhead of the incrementing variable and the loop control logic.
* **Using slice() and reverse() methods ("reverse")**:
	+ Pros: Can be faster than traditional for loops since it leverages the optimized implementations of `slice()` and `reverse()` in modern JavaScript engines.
	+ Cons: May require more memory allocation and copying of elements, especially for large datasets.

**Other Considerations**

Other factors that may affect performance in this benchmark include:

* The specific version of JavaScript being used (e.g., ECMAScript 6, ES7, etc.).
* The specifics of the browser or runtime environment being tested (e.g., Safari 17, Node.js v14.x, etc.).
* The size and complexity of the input dataset (`num`).

**Alternatives**

Some alternative approaches that could be considered for creating strings with asterisks include:

* Using a `while` loop instead of a traditional for loop.
* Utilizing modern JavaScript features like `Array.prototype.map()` or `String.prototype.repeat()`.
* Employing more advanced string manipulation techniques, such as using Unicode characters or regular expressions.

However, these alternatives may not be relevant to this specific benchmark, which is primarily focused on comparing the performance of two basic approaches.

for vs reverse (version: 0)

Comparing performance of: `reverse vs for`

Created: 2 years ago by: Guest

Go to the latest result

reverse

for

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

for vs reverse (version: 0)

Comparing performance of: reverse vs for

Created: 2 years ago by: Guest

Go to the latest result

reverse

for

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `reverse vs for`