Benchmark: wefiowjfoiewjfoiwef

Script Preparation code:

var str = '!foo bar baz';
var noop = Function.prototype;

Tests:

character index
if (str[0] === '!') noop();
charAt()
if (str.charAt(0) === '!') noop();
startsWith()
if (str.startsWith('!')) noop();
slice()
if (str.slice(0, 1) === '!') noop();
RegExp
const pattern = /^!/; if (pattern.test(str)) noop();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
character index
charAt()
startsWith()
slice()
RegExp

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach.

**Benchmark Overview**

The benchmark is designed to compare the performance of different methods for testing if a string starts with a specific character. The test cases are as follows:

1. `character index`: Tests if the first character of the string matches the expected value.
2. `charAt()`: Tests if the result of `str.charAt(0)` returns true when compared to the expected value.
3. `startsWith()`: Tests if the string starts with the expected value using the `startsWith()` method.
4. `slice()`: Tests if slicing the first character of the string and comparing it to the expected value is faster than other methods.
5. `RegExp`: Tests if a regular expression pattern matches the string.

**Methods Compared**

The benchmark compares five different methods for testing if a string starts with a specific character:

1. **Character Index**: Directly accessing the first character of the string using indexing (e.g., `str[0] === '!')`.
2. **charAt()**: Using the `charAt()` method to get the first character of the string and comparing it to the expected value.
3. **startsWith()**: Using the `startsWith()` method to check if the string starts with the expected value.
4. **Slice()**: Slicing the first character of the string using `str.slice(0, 1)` and comparing it to the expected value.
5. **RegExp**: Using a regular expression pattern (`^!`) to match the string.

**Pros and Cons**

Here's a brief summary of each method:

* **Character Index**: Fastest and most direct approach. However, it may not work as expected for strings with multiple consecutive special characters or Unicode characters that don't fit into a single code point.
* **charAt()**: More reliable than character index but slower due to the function call overhead. It's suitable for most use cases but may not be ideal for very large strings.
* **startsWith()**: The most modern and flexible approach, as it works with any string type (not just ASCII). However, it may be slower than other methods due to the method call overhead.
* **Slice()**: Less efficient than character index or charAt() because of the slicing operation. It's suitable for strings where only a single character is needed.
* **RegExp**: May be slower than other methods due to the regular expression engine's complexity. However, it provides a flexible way to match any pattern.

**Library and Special JS Features**

None of the methods require a specific library or special JavaScript features beyond what's built into the language (e.g., `String.prototype` for methods like `charAt()`).

The only notable exception is that `startsWith()` requires support for Unicode strings, as it uses the `Intl` API to handle string matching.

**Other Alternatives**

If none of these methods are satisfactory or if you need more advanced functionality, consider using:

* **Substrings**: Instead of slicing or accessing individual characters, you can create a substring from the beginning of the string up to the expected character.
* **Regular Expressions**: If you need to match any pattern within the string, not just a single character at the start.

**Benchmark Considerations**

When interpreting benchmark results:

* Look for the fastest method across all test cases. In this case, `character index` is the clear winner.
* Check for consistency across browsers and devices. The results provided suggest that Chrome 84 on Mac OS X 10.16.0 performs well in all test cases.
* Consider other factors like memory usage and thread safety if they're relevant to your specific use case.

Keep in mind that benchmarking is an art, and different hardware and software configurations may yield varying results.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_16_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36

Browser/OS: Chrome 84 on Mac OS X 10.16.0

View result in a separate tab

Test name	Executions per second
character index	3507037.5 Ops/sec
charAt()	3396388.8 Ops/sec
startsWith()	3402368.8 Ops/sec
slice()	2985060.8 Ops/sec
RegExp	2369607.8 Ops/sec

Related benchmarks:

wefiowjfoiewjfoiwef (version: 0)

Compare methods for testing string's beggining character.

Comparing performance of: character index vs charAt() vs startsWith() vs slice() vs RegExp

Created: 4 years ago by: Guest

Jump to the latest result

character index

charAt()

startsWith()

slice()

RegExp

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):