Benchmark: IndexOf vs Includes in string 24

Script Preparation code:

var string = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat'

Tests:

index
string[string.length - 1] === 't'
charAt
string.charAt(string.length - 1) === 't'

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
index
charAt

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
index	11023182.0 Ops/sec
charAt	11022814.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

MeasureThat.net provides a JavaScript microbenchmarking platform, where users can create and run benchmarks to compare different approaches for specific use cases. The provided benchmark measures the performance difference between two string manipulation methods: `indexOf()` versus `includes()`.

**Options Compared**

The benchmark compares two options:

1. **`string.indexOf(string.length - 1) === 't'`**: This option uses the `indexOf()` method to find the index of the last character `'t'` in the string. If the character is found, the function returns its index; otherwise, it returns `-1`.
2. **`string.charAt(string.length - 1) === 't'`**: This option uses the `charAt()` method to retrieve the last character of the string and compares it with `'t'`.

**Pros and Cons**

Both options have their advantages and disadvantages:

*   **`indexOf()`**: Pros:
    *   More efficient for large strings, as it only needs to scan up to the specified index.
    *   Fewer DOM accesses (if not using DOM elements).
*   Cons:
    *   May be slower for very short strings due to function call overhead.
    *   Returns `NaN` if the character is not found at the specified index.
*   **`charAt()`**: Pros:
    *   Can be faster for very short strings due to fewer function calls and DOM accesses.
    *   Returns a value directly (no need to compare).
*   Cons:
    *   More memory-intensive, as it creates an additional string object.
    *   May access more DOM elements if using DOM elements.

**Library Usage**

The benchmark uses the `string` object's built-in methods without any external libraries. This means that any optimizations or implementations specific to a particular JavaScript engine or environment may not be reflected in the benchmark results.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in this benchmark. It only relies on standard JavaScript functionality, making it easy for developers familiar with JavaScript to understand and reproduce.

**Other Alternatives**

If you were looking for alternative approaches to compare:

*   **`includes()`**: This method is not part of the original benchmark but can be tested as an alternative to `indexOf()`.
*   **Regular Expressions (RegExp)**: Using RegExp to find a specific character or pattern might provide additional performance variations.
*   **Substrings manipulation**: Using string slicing (`string.slice(-1)`) could also serve as an alternative.

**Benchmark Results**

The latest benchmark results show that:

*   The `indexOf()` method is significantly faster for this particular use case (with 110,231 executions per second).
*   However, when using shorter strings or in situations where there's only one character to compare, the performance difference may not be as pronounced.

Overall, this benchmark provides a clear insight into how different string manipulation methods perform in various scenarios.

Related benchmarks:

IndexOf vs Includes in string 24 (version: 1)

Banana

Comparing performance of: index vs charAt

Created: 2 years ago by: Registered User

Jump to the latest result

index

charAt

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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