Benchmark: tests fir startwith polyfills

Script Preparation code:

var searchInMe = 'IstartwithIstartwithIstartwithIstartwithIstartwithIstartwithIstartwithIstartwithIstartwithIstartwithIstartwithIstartwith';
var searchInMe2 = 'InotstartwithInotstartwithInotstartwithInotstartwithInotstartwithInotstartwithInotstartwithInotstartwithInotstartwith11';
var searchForMe = 'Istartwith';
var searchForMeEr = /^Istartwith/;

Tests:

startWith native
searchInMe.startsWith(searchForMe); searchInMe2.startsWith(searchForMe);
indexof
searchInMe.indexOf(searchForMe) === 0; searchInMe2.indexOf(searchForMe) === 0;
lastIndexOf
searchInMe.lastIndexOf(searchForMe, 0) === 0; searchInMe2.lastIndexOf(searchForMe, 0) === 0;
regex
searchForMeEr.test(searchInMe); searchForMeEr.test(searchInMe2);
substr
searchInMe.substr(0, searchForMe.length) === searchForMe; searchInMe2.substr(0, searchForMe.length) === searchForMe;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
startWith native
indexof
lastIndexOf
regex
substr

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark definition json represents a test case that compares the performance of different string comparison methods in JavaScript.

**String Comparison Methods Compared**

The test cases compare four string comparison methods:

1. **`startsWith()`**: A method that checks if a string starts with another string.
2. **`indexOf()`**: A method that returns the index of the first occurrence of a substring within a string, or -1 if not found.
3. **`lastIndexOf()`**: A method that returns the last index of a substring within a string, or -1 if not found.
4. **`substr()`**: A method that extracts a subset of characters from a string.

**Pros and Cons of Each Approach**

Here's a brief overview of each approach:

* **`startsWith()`**:
	+ Pros: Fast and efficient for most cases.
	+ Cons: May return false positives if the start character is not unique in the string (e.g., "hello" starts with both "h" and "j").
* **`indexOf()`**:
	+ Pros: Can be used to find the first occurrence of a substring, which can be useful for searching.
	+ Cons: May be slower than `startsWith()` for most cases, as it needs to search through the entire string.
* **`lastIndexOf()`**:
	+ Pros: Fast and efficient for finding the last occurrence of a substring.
	+ Cons: May not be suitable for all use cases, as it returns -1 if the substring is not found.
* **`substr()`**:
	+ Pros: Can be used to extract a subset of characters from a string.
	+ Cons: May not be suitable for comparing entire strings, as it only extracts a portion of the string.

**Library and Syntax Used**

In this benchmark, the `test()` function is used to compare the performance of the different string comparison methods. The `test()` function is a part of the RegExp object in JavaScript, which provides a way to test if a string matches a regular expression pattern.

**Special JS Feature or Syntax**

None mentioned in the provided code.

**Other Alternatives**

If you need to perform string comparisons in JavaScript, other alternatives include:

* Using the `===` operator for exact string matching
* Using the `includes()` method for searching within a string
* Using the `replace()` method for replacing substrings

It's worth noting that MeasureThat.net provides a more efficient and reliable way to compare the performance of different string comparison methods, as it uses a standardized benchmarking framework.

Related benchmarks:

tests fir startwith polyfills (version: 0)

Comparing performance of: startWith native vs indexof vs lastIndexOf vs regex vs substr

Created: 9 years ago by: Guest

Jump to the latest result

startWith native

indexof

lastIndexOf

regex

substr

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):