Benchmark: .endsWith vs last char check regex

Script Preparation code:

var stringToCheck = 'alksjdflaksjdlkajtlkadjsta;ksdglkasdjfadsfaf{';

var result = null;

Tests:

.endsWith
result = stringToCheck.endsWith("[") || stringToCheck.endsWith("{");
regex
var regexString = /\[|\{{1}$/gm result = regexString.test( stringToCheck );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.endsWith
regex

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares two approaches to check if a string ends with a certain character or substring: using the `.endsWith()` method and using a regular expression (regex).

**Options Compared**

There are two options compared:

1. **.endsWith()**: This is a built-in JavaScript method that checks if a string ends with a specified value.
2. **Regex**: This approach uses a regular expression to match the target character or substring at the end of the string.

**Pros and Cons of Each Approach**

* `.endsWith()`:
	+ Pros: Simple, easy to understand, and widely supported by modern browsers.
	+ Cons: Can be slower than regex for certain use cases, as it involves an additional function call and potentially some extra processing.
* Regex:
	+ Pros: More powerful and flexible, can handle complex matching scenarios, and often faster than `.endsWith()` due to its compiled nature.
	+ Cons: Can be more difficult to read and maintain, especially for those without extensive regex experience.

**Library/Module Used**

In this benchmark, no specific library or module is used. The regex approach relies on the built-in `RegExp` constructor in JavaScript.

**Special JS Feature/Syntax**

None are mentioned explicitly in this benchmark. However, it's worth noting that the `.endsWith()` method was introduced in ECMAScript 2015 (ES6), so older browsers may not support it.

**Alternative Approaches**

Other approaches to check if a string ends with a certain character or substring could include:

* Using `slice()` and checking the last few characters of the string
* Using `indexOf()` and checking for the negative result
* Using a custom loop to iterate over the string from the end

However, these alternatives may not be as efficient or elegant as the `.endsWith()` method or regex approach.

**Benchmark Preparation Code**

The script preparation code defines two variables:

1. `stringToCheck`: The input string to test.
2. `result`: The variable that will store the result of the benchmark.

**Individual Test Cases**

There are two test cases:

1. **.endsWith()**: This test case compares the performance of using the `.endsWith()` method with a hardcoded value (`"[\")`) against another hardcoded value (`"}"`).
2. **Regex**: This test case uses regex to match the target character or substring at the end of the input string.

The benchmark results show that the regex approach outperforms the `.endsWith()` method, likely due to its compiled nature and more efficient matching algorithm.

Related benchmarks:

.endsWith vs last char check regex (version: 0)

Comparing performance of: .endsWith vs regex

Created: 3 years ago by: Guest

Jump to the latest result

.endsWith

regex

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):