Benchmark: Performance Test: substring vs substr vs sliceyy

Script Preparation code:

var string = "Iam the god of hellfire, and I bring you...";
var search = "Iam";

function startsWith(haystack, needle) {
		var searchLength = needle.length;

		var index = -1;
		while (++index < searchLength) {
			if (haystack.charCodeAt(index) != needle.charCodeAt(index)) {
                return false;
            }
        }
        return true;
    }

Tests:

slice
var poly = startsWith(string, search);
substring
var natiiv = string.startsWith(search);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring

Fastest: N/A

Slowest: N/A

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

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Let's break down what's being tested in this benchmark.

The test is comparing three different approaches for substring-related operations:

1. **`string.startsWith(search)`**: This method returns `true` if the string starts with the specified search value, and `false` otherwise. It's a built-in JavaScript method that uses an optimized algorithm under the hood.
2. **`startsWith(haystack, needle)`**: This is a custom implementation provided in the benchmark preparation code. It manually iterates over the haystack string to check if it starts with the needle substring. The purpose of this test is to compare its performance with the built-in `startsWith()` method.
3. **`string.slice(searchLength)`** (assumed, as "sliceyy" might be a typo): This method returns a new string containing all characters from the specified index to the end of the original string. However, in this context, it seems that the intention is to compare its performance with `startsWith()` and possibly another approach, which might not be directly related to slicing.

Now, let's discuss the pros and cons of each approach:

**`string.startsWith(search)`**:

Pros:

* Optimized for performance by using a specialized algorithm.
* Widely supported across browsers and environments.
* Easy to use and understand.

Cons:

* Might not be as customizable or flexible as other approaches.
* Limited control over implementation details (e.g., handling Unicode characters).

**`startsWith(haystack, needle)`**:

Pros:

* Allows for fine-grained control over the comparison process.
* Can handle edge cases more effectively than built-in methods.

Cons:

* Manually implemented, which can lead to performance overhead due to iteration and conditional checks.
* Might not be as optimized or efficient as built-in methods.

The other alternatives that are likely being compared in this benchmark (though not explicitly mentioned) might include:

1. **`indexOf()`**: A method that returns the index of the first occurrence of the specified value, or -1 if not found. This could be used to implement a similar comparison logic, but with an additional step to check for presence.
2. **Regular expressions** (e.g., ` RegExp.test() `): These can provide more advanced matching capabilities, including handling Unicode characters and complex patterns. However, they might add unnecessary overhead due to parsing and compilation.
3. **Custom implementation using `Array.prototype.some()`**: This method iterates over the array and checks if any element matches the condition. It could be used as an alternative to the manual iteration in `startsWith(haystack, needle)`.

Keep in mind that this is speculative, as the benchmark only explicitly compares `startsWith()` with a custom implementation. The actual alternatives being tested might differ based on the specific requirements of the project or the goals of the performance test.

Related benchmarks:

Performance Test: substring vs substr vs sliceyy (version: 0)

Comparing performance of: slice vs substring

Created: 2 years ago by: Guest

Jump to the latest result

slice

substring

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):