Benchmark: startswith vs direct comparison

HTML Preparation code:

<div></div>

Script Preparation code:

window.regexStart = /^test/;
window.regexEnd = /test$/;
window.match = 'test';
window.matchLength = window.match.length;
var data = window.data = [];
const possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var TOTAL_STRINGS = window.TOTAL_STRINGS = 100000;

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

function makeRandomString(len) {
  var text = "";
  for( var i=0; i < len; i++ ) {
    text += possible.charAt(getRandomInt(possible.length));
  }
  return text;
}

while (data.length < TOTAL_STRINGS) {
  data.push(makeRandomString(getRandomInt(20)));
}

Tests:

direct
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var regex = window.regexStart; var test = 'test'; var res = 0; while (x < TOTAL_STRINGS) { const str = data[x]; if (str === test) {res += 1;} x += 1; } console.log(res)
startsWith
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; var test = 'test'; var res = 0; while (x < TOTAL_STRINGS) { const str = data[x]; if (str.startsWith(test)) { res += 1; } x += 1; } console.log(res);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
direct
startsWith

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case, where two approaches are compared: direct comparison and `startsWith` method.

**Options Compared**

Two options are being compared:

1. **Direct Comparison**: This approach uses the `===` operator to compare each string in the `data` array with the fixed string `'test'`. If the strings match, it increments a counter `res`.
2. **StartsWith Method**: This approach uses the `startsWith()` method of the string object to check if the first character of each string in the `data` array is equal to `'t'`, which would indicate that the string starts with `'test'`. If true, it increments the same counter `res`.

**Pros and Cons**

1. **Direct Comparison**
	* Pros:
		+ Simple and straightforward implementation.
		+ Fast execution since it only requires a simple comparison.
	* Cons:
		+ May be slow for large datasets due to the overhead of checking every character in each string.
2. **StartsWith Method**
	* Pros:
		+ More efficient than direct comparison, especially for large datasets, as it uses an optimized algorithm under the hood.
		+ Handles partial matches correctly (e.g., strings like `'test'`).
	* Cons:
		+ Requires a call to the `startsWith()` method, which can be slower due to function overhead.

**Library and Special JS Features**

There are no explicit libraries used in this benchmark. However, it's worth noting that the JavaScript engine being tested (e.g., V8 for Chrome) may utilize various optimizations and caching mechanisms under the hood.

**Other Considerations**

* **Memory Usage**: Both approaches have a time complexity of O(n), where n is the number of strings in the `data` array. However, direct comparison may require more memory due to the need to store all characters in each string, while `startsWith()` only stores the first character.
* **Cacheability**: Some JavaScript engines, like V8, have cache mechanisms that can improve performance for certain types of operations. In this case, the `startsWith()` method might benefit from caching, but direct comparison does not.

**Alternatives**

Some alternative approaches to consider:

1. **Regular Expressions**: Using a regular expression (e.g., `/test/`) instead of the `startsWith()` method could provide similar performance benefits and additional features like partial matching.
2. **Hash-Based Comparison**: Instead of using direct comparison or `startsWith()`, you could use a hash-based approach to quickly determine whether two strings are equal or have a common prefix.

Keep in mind that these alternatives may introduce additional complexity, dependencies, or overhead, which should be carefully evaluated depending on the specific requirements and constraints of your project.

Related benchmarks:

startswith vs direct comparison (version: 0)

Comparing performance of: direct vs startsWith

Created: 5 years ago by: Guest

Jump to the latest result

direct

startsWith

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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