Benchmark: re.match vs re.test vs str.startsWith vs str.indexOf

Script Preparation code:

var path = "/models/";

Tests:

re.match (regexp)
path.match(/^\/models\//);
re.match (string)
path.match("^/models/");
re.test
/^\/models\//.test(path);
str.startsWith
path.startsWith("/models/");
str.indexOf
path.indexOf("/models/") === 0;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
re.match (regexp)
re.match (string)
re.test
str.startsWith
str.indexOf

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:82.0) Gecko/20100101 Firefox/82.0

Browser/OS: Firefox 82 on Fedora

View result in a separate tab

Test name	Executions per second
re.match (regexp)	10158847.0 Ops/sec
re.match (string)	2811995.0 Ops/sec
re.test	14524993.0 Ops/sec
str.startsWith	26785078.0 Ops/sec
str.indexOf	24555112.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**Benchmark Overview**

The provided benchmark measures the performance difference between four string comparison methods: `re.match` (regular expression), `re.test`, `str.startsWith`, and `str.indexOf`. These methods are used to check if a string starts with a specific prefix.

**Test Cases**

Each test case has two variations:

1. **Regular Expression**: Using the `RegExp` constructor to create a regular expression object.
	* Example: `path.match(/^\\/models\\//);`
2. **String Literal**: Using a plain string literal.
	* Example: `path.match("^/models/")`

**Options Compared**

The benchmark compares the performance of:

1. **Regular Expressions (re.match)**: Using regular expressions to match the prefix.
2. **String Literals (re.test)**: Comparing the string directly using `test()`.
3. **startsWith**: Using a built-in method to check if the string starts with the prefix.
4. **indexOf**: Using an indexed method to find the first occurrence of the prefix.

**Pros and Cons**

1. **Regular Expressions (re.match)**:
	* Pros: Portable, flexible, and can be used for more complex patterns.
	* Cons: Can be slower due to compilation and parsing overhead.
2. **String Literals (re.test)**:
	* Pros: Fast and lightweight, as it's just a string comparison.
	* Cons: Limited flexibility, as it only checks exact matches.
3. **startsWith**:
	* Pros: Fast and simple, built-in method in JavaScript.
	* Cons: May not be as flexible as regular expressions or string literals.
4. **indexOf**:
	* Pros: Can be used for more complex searches (e.g., finding the first occurrence of a substring).
	* Cons: May be slower than simple `startsWith` checks, especially for large strings.

**Library and Purpose**

The benchmark uses the `RegExp` object from JavaScript's built-in library. The `RegExp` constructor is used to create regular expression objects, which are then used in the test cases.

**Special JS Features or Syntax**

This benchmark does not specifically target any special JavaScript features or syntax. It focuses on comparing four common string comparison methods.

**Other Alternatives**

If you need more flexible or performance-critical string matching, consider using:

1. **Perl-compatible regular expressions (PCRE)**: Can offer better performance and flexibility than native JavaScript regular expressions.
2. **NativeArrayBuffer-based string comparisons**: May provide better performance for large strings or use cases where memory efficiency is crucial.

Keep in mind that the best approach depends on your specific use case, performance requirements, and trade-offs between flexibility, readability, and speed.

Related benchmarks:

re.match vs re.test vs str.startsWith vs str.indexOf (version: 0)

Comparing performance of: re.match (regexp) vs re.match (string) vs re.test vs str.startsWith vs str.indexOf

Created: 2 years ago by: Guest

Jump to the latest result

re.match (regexp)

re.match (string)

re.test

str.startsWith

str.indexOf

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):