Benchmark: Compare chars - MeasureThat.net

HTML Preparation code:

<input />

Script Preparation code:

window.input = document.querySelector('input');
window.input.value = 'This is very long text very long text';
window.vWas = input.value;
window.vSame = input.value;

input.value += "!!!";
window.vDiff = input.value;

Tests:

Compare by char
for (let i = 0; i < vDiff.length; ++i) { if (vWas[i] !== vDiff[i]) { break; } }
Compare by char-code
for (let i = 0; i < vDiff.length; ++i) { if (vWas.charCodeAt(i) !== vDiff.charCodeAt(i)) { break; } }
Compare whole strings (different)
let isChanged = vWas !== vDiff;
Compare whole strings (same)
let isChanged = vWas === vSame;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Compare by char
Compare by char-code
Compare whole strings (different)
Compare whole strings (same)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36

Browser/OS: Chrome 115 on Windows

View result in a separate tab

Test name	Executions per second
Compare by char	66957.2 Ops/sec
Compare by char-code	65943.2 Ops/sec
Compare whole strings (different)	3962759.5 Ops/sec
Compare whole strings (same)	3795239.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring the performance of string comparison in JavaScript can be a bit complex, but I'll break it down for you.

The benchmark compares three different approaches to compare two strings: `vWas` and `vDiff`.

**Approach 1: Compare by character (using `!==` operator)**

This approach iterates over each character of the string using a traditional for loop. The comparison is done using the `!==` operator, which checks if the characters at the current index are different.

Pros:

* Simple and straightforward implementation.
* Does not require any special library or syntax.

Cons:

* Has a higher overhead due to the use of the `===` and `!==` operators, which can lead to more function calls and memory allocations.

**Approach 2: Compare by character code (using `charCodeAt()` method)**

This approach is similar to Approach 1 but uses the `charCodeAt()` method to get the ASCII code of each character. The comparison is done using the same `!==` operator as before.

Pros:

* This approach can be slightly faster than Approach 1 because it avoids the overhead of the `===` and `!==` operators.
* However, this approach still has a higher overhead due to the use of `charCodeAt()` method, which can lead to more function calls and memory allocations.

Cons:

* Requires the use of the `charCodeAt()` method, which may not be supported in older browsers or environments.

**Approach 3: Compare whole strings (using `===` operator)**

This approach simply compares the two strings using the `===` operator. If they are equal, it sets a flag (`isChanged`) to true; otherwise, it sets the flag to false.

Pros:

* Simple and straightforward implementation.
* Does not require any special library or syntax.

Cons:

* This approach is generally slower than the other two approaches because of the overhead of comparing the entire string using the `===` operator.

Now, let's talk about some additional considerations:

* **String comparison algorithms**: JavaScript has several built-in string comparison algorithms, including the ASCII-based comparison and Unicode-based comparison. The choice of algorithm depends on the specific requirements of the application.
* **String normalization**: When comparing strings, it's essential to consider the impact of string normalization on the results. Normalization can affect the comparison outcome by converting equivalent strings into a standardized format.

The benchmark result shows that Approach 3 (Compare whole strings) is the fastest approach among the three, while Approach 1 (Compare by character) has the highest overhead.

In terms of alternatives, there are other approaches to comparing strings in JavaScript, such as using regular expressions or specialized libraries like Lodash. However, these approaches may have different trade-offs in terms of performance, complexity, and maintenance.

Here's a brief overview of some alternative string comparison methods:

* **Regular Expressions**: Regular expressions can be used to compare strings by specifying patterns and matching rules.
* **Lodash library**: Lodash provides several utility functions for comparing arrays and objects, including string comparison.
* **NativeString.prototype.compare() method**: This method is available in some browsers and environments, allowing for native string comparison.

Keep in mind that the choice of approach depends on the specific requirements and constraints of your project.

Related benchmarks:

Compare chars (version: 10)

Comparing performance of: Compare by char vs Compare by char-code vs Compare whole strings (different) vs Compare whole strings (same)

Created: one year ago by: Registered User

Jump to the latest result

Compare by char

Compare by char-code

Compare whole strings (different)

Compare whole strings (same)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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