Benchmark: endsWith vs Regex2

Tests:

Regex
/(^|[^-])-{2}$/.test("this is a test-- ")
endsWith
"this is a test--".endsWith("--")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
endsWith

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Browser/OS: Chrome 123 on Windows

View result in a separate tab

Test name	Executions per second
Regex	34084012.0 Ops/sec
endsWith	107732112.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the explanation into smaller sections to make it easier to understand.

**Benchmark Definition and Script Preparation Code**

The provided benchmark definition is a JSON object that represents the test case. It contains two test cases:

1. `"/(^|[^-])-{2}$/.test("this is a test-- ")"`
	* This is a regular expression (Regex) test case.
	* The Regex pattern `/^$-$-\)/` matches any string that ends with two consecutive hyphens `-`.
	* The `.test()` method checks if the input string ` "this is a test-- "` matches this pattern.
2. `"\"this is a test--\".endsWith(\"--\")"`
	* This is an implementation test case for the `endsWith()` method.
	* The `endsWith()` method is a built-in JavaScript method that returns true if the input string ends with the specified substring.

**Options Compared**

The two options compared in this benchmark are:

1. **Regex**: A regular expression-based approach to check if a string ends with a specific substring.
2. **endsWith() Method**: A built-in JavaScript method that checks if a string ends with a specific substring.

**Pros and Cons of Each Approach**

1. **Regex**
	* Pros:
		+ Can be used for more complex string matching tasks.
		+ Can be optimized using flags and performance tweaks (e.g., `g`, `i`, `m` flags).
	* Cons:
		+ Can be slower and less efficient than the built-in `endsWith()` method.
		+ Requires explicit error handling and edge case checking.
2. **endsWith() Method**
	+ Pros:
		+ Fast and efficient.
		+ Built-in implementation with optimized performance.
		+ Less code to write and maintain.
	* Cons:
		+ Only suitable for simple string matching tasks (end-of-string checks).
		+ May not be as flexible or powerful as Regex.

**Library Usage**

There is no explicit library usage in this benchmark, but it's worth noting that the `endsWith()` method uses a built-in JavaScript implementation that relies on the ECMAScript standard.

**Special JS Feature or Syntax**

None mentioned. The benchmark only compares two simple string matching approaches.

**Other Alternatives**

If you want to compare other approaches for checking if a string ends with a specific substring, some alternatives could be:

1. **Using the `toString()` method**: You can convert the string to a primitive type using `toString()` and then check its length.
```javascript
var str = "this is a test--";
if (str.toString().length === 7) {
  // ...
}
```
2. **Using a custom loop**: You can use a simple loop to iterate over the characters in the string from the end.
```javascript
var str = "this is a test--";
for (var i = str.length - 1; i >= 0; i--) {
  if (str[i] === '-') {
    // ...
  }
}
```
Keep in mind that these alternatives are less efficient and less elegant than the `endsWith()` method or Regex.

Related benchmarks:

endsWith vs Regex2 (version: 0)

Comparing performance of: Regex vs endsWith

Created: 2 years ago by: Guest

Jump to the latest result

Regex

endsWith

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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