Benchmark: Repeating String

Tests:

Simple for loop
function repeatify(string, repetitions) { if (repetitions < 0 || repetitions === Infinity) { throw new RangeError('Invalid repetitions number'); } let result = ''; for (let i = 0; i < repetitions; i++) { result += string; } return result; } repeatify('*', 10000);
Extended for loop
function repeatify2(string, repetitions) { if (repetitions < 0 || repetitions === Infinity) { throw new RangeError('Invalid repetitions number'); } const isEven = repetitions % 2 === 0; const iterations = Math.floor(repetitions / 2); const stringTwice = string + string; let result = ''; for (let i = 0; i < iterations; i++) { result += stringTwice; } if (!isEven) { result += string; } return result; } repeatify2('*', 10000);
Log based
function repeatify3(string, repetitions) { if (repetitions < 0 || repetitions === Infinity) { throw new RangeError('Invalid repetitions number'); } const cache = new Map(); function repeat(string, repetitions) { if (repetitions === 0) { return ''; } const log = Math.floor(Math.log2(repetitions)); let result; if (cache.has(log)) { result = cache.get(log); } else { result = string; for (let i = 1; i <= log; i++) { result += result; cache.set(i, result); } } const repetitionsProcessed = Math.pow(2, log); const repetitionsLeft = repetitions - repetitionsProcessed; return result + repeat(string, repetitionsLeft); } return repeat(string, repetitions); } repeatify3('*', 10000);
Array approach
function repeatify4(string, repetitions) { if (repetitions < 0 || repetitions === Infinity) { throw new RangeError('Invalid repetitions number'); } return Array(repetitions + 1).join(string); } repeatify4('*', 10000);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Simple for loop
Extended for loop
Log based
Array approach

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'll provide an explanation of the benchmark, options compared, pros and cons, library usage, special JS features, and alternative approaches.

**Benchmark Overview**

The Repeating String benchmark measures the performance of different approaches to create a string by repeating a given input string a specified number of times. The goal is to determine which approach is the fastest and most efficient.

**Options Compared**

There are four test cases:

1. **Simple for loop**: This implementation uses a traditional `for` loop to repeat the string.
2. **Extended for loop**: This implementation uses an optimized `for` loop that reduces the number of iterations by using arithmetic operations instead of increments.
3. **Log based**: This implementation uses bitwise operations and caching to reduce the number of iterations required.
4. **Array approach**: This implementation uses JavaScript's built-in `join()` method to repeat the string.

**Pros and Cons**

* **Simple for loop**:
	+ Pros: Easy to understand, straightforward implementation.
	+ Cons: Can be slow due to unnecessary increments in the loop variable.
* **Extended for loop**:
	+ Pros: Optimized for performance, reduces iterations using arithmetic operations.
	+ Cons: May require additional computation and caching.
* **Log based**:
	+ Pros: Highly optimized for performance, uses bitwise operations and caching.
	+ Cons: More complex implementation, requires understanding of binary logarithms and caching.
* **Array approach**:
	+ Pros: Simple and easy to understand, leverages built-in `join()` method.
	+ Cons: May not be the most efficient due to unnecessary array creation.

**Library Usage**

There is no explicit library usage in any of the test cases. However, some implementations (e.g., `Log based`) might use internal libraries or functions provided by JavaScript engines (e.g., Firefox's `Math.log2()`).

**Special JS Features**

The `repeatify3` implementation uses a special feature called " memoization" through the `Map` data structure to cache intermediate results. This is an advanced optimization technique that can significantly improve performance.

**Alternative Approaches**

Other approaches to repeating a string could include:

* Using `String.prototype.repeat()` (introduced in ECMAScript 2015):
```javascript
var result = '*'.repeat(10000);
```
* Utilizing `Buffer` or `TypedArray` for optimized repeated operations:
```javascript
const buffer = Buffer.alloc(10000 * string.length, '*');
```
These alternatives might offer different trade-offs in terms of performance, readability, and complexity.

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:50.0) Gecko/20100101 Firefox/50.0

Browser/OS: Firefox 50 on Mac OS X 10.12

View result in a separate tab

Test name	Executions per second
Simple for loop	6040.2 Ops/sec
Extended for loop	11658.2 Ops/sec
Log based	127897.6 Ops/sec
Array approach	1041.9 Ops/sec

Related benchmarks:

Repeating String (version: 0)

Comparing performance of: Simple for loop vs Extended for loop vs Log based vs Array approach

Created: 7 years ago by: Guest

Jump to the latest result

Simple for loop

Extended for loop

Log based

Array approach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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