Benchmark: test start with v2

Script Preparation code:

function startsWith(str, a) {
	return str.substring(0, a.length) === a
}
function startsWith2(str, a) {
	return str.indexOf(a) === 0
}

Tests:

regex
/^user\.view:/.test('user.view:1337'); /^user\.list:/.test('user.view:1337')
startsWith
'user.view:1337'.startsWith('user.view:') 'user.view:1337'.startsWith('user.list:')
custom startsWith
startsWith('user.view:1337', 'user.view:') startsWith('user.view:1337', 'user.list:')
indexOf
'user.view:1337'.indexOf('user.view:') === 0 'user.view:1337'.indexOf('user.list:') === 0
substring
'user.view:1337'.substring(0, 10) === 'user.view:' 'user.view:1337'.substring(0, 10) === 'user.view:'
custom startsWith2
startsWith('user.view:1337', 'user.view:') startsWith('user.view:1337', 'user.list:')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex
startsWith
custom startsWith
indexOf
substring
custom startsWith2

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.

Let's break down the benchmark and its components.

**Benchmark Definition JSON**

The provided JSON defines two main components of the benchmark:

1. **Script Preparation Code**: This is a JavaScript snippet that sets up some functions:
	* `startsWith(str, a)`: Tests if a string starts with a given substring.
	* `startsWith2(str, a)`: Another implementation of the same test as above (not used in this benchmark).
	* These two functions are not actually used in the benchmark, but they seem to be there for some reason.
2. **Html Preparation Code**: This is empty, so no HTML setup or preparation code is provided.

**Individual Test Cases**

The benchmark consists of six test cases, each defining a different scenario:

1. **Regex**: Tests if the string "user.view:1337" matches a regular expression that starts with "/^user\.view:"/".
2. **startsWith**: Tests if the string "user.view:1337" starts with either "user.view:" or "user.list:".
3. **Custom startsWith**: Same as above, but with a custom implementation of `startsWith` using function calls.
4. **IndexOf**: Tests if the index of "user.view:1337" is 0 when looking for "user.view:" or "user.list:".
5. **Substring**: Tests if the substring of "user.view:1337" from index 0 to 10 equals "user.view:" (twice).
6. **Custom startsWith2**: Same as above, but with another custom implementation of `startsWith`.

**Options Compared**

The benchmark compares different approaches:

* Regex vs. `startsWith` vs. `custom startsWith`
* Regex vs. `indexOf`
* `startsWith` vs. `custom startsWith`
* `startsWith` vs. `custom startsWith2`

**Pros and Cons of Different Approaches**

Here's a brief summary:

1. **Regex**: Fast, but may be less readable or maintainable for complex patterns.
	* Pros: Efficient, widely supported.
	* Cons: Error-prone, can be slow for very large inputs.
2. **startsWith**: Simple and easy to understand, but may not be optimized for performance.
	* Pros: Easy to implement, intuitive.
	* Cons: May be slower than regex or custom implementations.
3. **Custom startsWith**: Can be optimized for specific use cases, but requires more effort to maintain.
	* Pros: Optimized for performance, can be customized for specific requirements.
	* Cons: More complex, may require additional effort for maintenance.

**Library Used**

There is no explicitly stated library used in the benchmark. However, it's likely that the browser itself uses a regex engine or an implementation of `startsWith` under the hood.

**Special JS Feature or Syntax**

None are mentioned.

**Alternatives**

Some alternative approaches to testing string matching could include:

1. **Using a dedicated library**: Instead of implementing custom functions, use a well-maintained and optimized library like Lodash's `startsWith` function.
2. **String manipulation libraries**: Libraries like Sindreorg's `string.prototype.startsWith` or others might offer more efficient implementations.

In conclusion, the benchmark tests different approaches to testing string matching: regex, `startsWith`, custom implementations, and indexing. The results will likely show that regex is the fastest but may be less readable, while custom implementations can be optimized for performance but require more effort to maintain.

Related benchmarks:

test start with v2 (version: 0)

Comparing performance of: regex vs startsWith vs custom startsWith vs indexOf vs substring vs custom startsWith2

Created: 3 years ago by: Guest

Jump to the latest result

regex

startsWith

custom startsWith

indexOf

substring

custom startsWith2

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):