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

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/");

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

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36

Browser/OS: Chrome 106 on Linux

View result in a separate tab

Test name	Executions per second
re.match (regexp)	6873218.0 Ops/sec
re.match (string)	2293572.5 Ops/sec
re.test	7971823.5 Ops/sec
str.startsWith	7954053.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares the performance of three different methods to check if a string starts with a certain pattern: `re.match`, `str.startsWith`, and `re.test`.

**Options Compared**

1. **`re.match` (regexp)**: This method uses a regular expression to search for a match at the beginning of the string. It returns a boolean value indicating whether a match was found.
2. **`re.match` (string)**: Similar to the previous one, but it directly searches for a match in the string instead of using a regexp.
3. **`str.startsWith`**: This method checks if the entire string starts with the specified prefix.

**Pros and Cons**

1. **`re.match` (regexp)**:
	* Pros: Can be more flexible and powerful when dealing with complex patterns, as it can use regular expression syntax.
	* Cons: May have slower performance compared to `str.startsWith`, especially for simple cases, since it needs to compile the regexp pattern beforehand.
2. **`re.match` (string)**:
	* Pros: Faster than `re.match (regexp)` for simple cases, as it doesn't need to compile a pattern.
	* Cons: Limited flexibility and power compared to `re.match (regexp)`.
3. **`str.startsWith`**:
	* Pros: Fastest of the three options, especially for simple cases with short prefixes.
	* Cons: May not work as expected for non-string inputs or when dealing with complex patterns.

**Library and Purpose**

The benchmark uses the following libraries:

1. **RegExp**: A JavaScript built-in object that provides support for regular expressions.
2. **String.prototype.startsWith**: A method on the String prototype that checks if the string starts with the specified prefix.

Both RegExp and String.prototype.startsWith are essential functions in JavaScript for working with strings, but they serve different purposes: one is a low-level API for regular expression matching, while the other is a high-level method for simple string comparison.

**Special JS Features or Syntax**

There's no specific special JS feature or syntax being tested in this benchmark. However, it's worth noting that RegExp and String.prototype.startsWith use JavaScript's regular expression engine internally.

**Alternative Approaches**

Other approaches to check if a string starts with a certain pattern include:

1. **Using `indexOf()`**: Checking if the index of the first occurrence of the prefix is -1.
2. **Using a custom function**: Writing a custom function that manually checks for the prefix at the beginning of the string.

Keep in mind that these alternative approaches may have varying performance and complexity compared to using RegExp or String.prototype.startsWith.

Related benchmarks:

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

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

Created: 2 years ago by: Guest

Jump to the latest result

re.match (regexp)

re.match (string)

re.test

str.startsWith

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):