Benchmark: Case insensitive string comparison: toLowerCase vs localeCompare vs toUpperCase

Script Preparation code:

var a = "John Doe"
var b = "john doe"
var c = "john smith"
var o = {
    sensitivity: 'base'
}

Tests:

toLowerCase()
a.toLowerCase() === b.toLowerCase()
localeCompare()
a.localeCompare(b,undefined,o)
toLowerCase() FAIL
c.toLowerCase() === b.toLowerCase()
localeCompare() FAIL
c.localeCompare(b,undefined,o)
toUpperCase()
a.toUpperCase() === b.toUpperCase()
toUpperCase() FAIL
c.toUpperCase() === b.toUpperCase()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
toLowerCase()
localeCompare()
toLowerCase() FAIL
localeCompare() FAIL
toUpperCase()
toUpperCase() FAIL

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/109.0.0.0 Safari/537.36

Browser/OS: Chrome 109 on Windows

View result in a separate tab

Test name	Executions per second
toLowerCase()	10032695.0 Ops/sec
localeCompare()	204295.2 Ops/sec
toLowerCase() FAIL	9071660.0 Ops/sec
localeCompare() FAIL	206662.9 Ops/sec
toUpperCase()	8844617.0 Ops/sec
toUpperCase() FAIL	8664905.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided JSON represents a benchmark that tests the performance of three different string comparison methods in JavaScript: `toLowerCase()`, `localeCompare()`, and `toUpperCase()`. The test compares the execution times of these methods on the same input strings, with varying levels of case sensitivity.

**Options Compared**

1. **`toLowerCase()`**: This method converts the entire string to lowercase.
2. **`localeCompare()`**: This method compares two strings in a locale-sensitive manner, taking into account the locale's collation rules and formatting preferences.
3. **`toUpperCase()`**: This method converts the entire string to uppercase.

**Pros and Cons of Each Approach**

1. **`toLowerCase()`**:
	* Pros: Simple and fast, as it only needs to iterate over the characters in the string.
	* Cons: May not work correctly for strings with non-ASCII characters or complex formatting rules.
2. **`localeCompare()`**:
	* Pros: Takes into account locale-specific rules and formatting preferences, making it suitable for internationalization and localization applications.
	* Cons: Can be slower than `toLowerCase()` due to its more complex algorithm and potential overhead from locale setup.
3. **`toUpperCase()`**:
	* Pros: Fast and simple, as it only needs to iterate over the characters in the string.
	* Cons: Similar to `toLowerCase()`, may not work correctly for strings with non-ASCII characters or complex formatting rules.

**Library Usage**

None of the test cases use any external libraries.

**Special JS Features or Syntax**

No special JavaScript features or syntax are used in this benchmark. The tests only utilize standard JavaScript methods and built-in functions.

**Other Alternatives**

In addition to these three methods, other string comparison techniques exist, such as:

1. **Using regular expressions**: Regular expressions can be used to compare strings with complex patterns and formatting rules.
2. **Using the `String.prototype.localeCompare()` method with a custom locale**: This allows developers to customize the locale-specific rules and formatting preferences for their application.
3. **Using a dedicated string comparison library**: Libraries like ICU or CLDR provide more advanced string comparison functionality, including support for multiple locales and complex formatting rules.

However, these alternatives are not part of the standard JavaScript API and may require additional setup or external dependencies.

Related benchmarks:

Case insensitive string comparison: toLowerCase vs localeCompare vs toUpperCase (version: 0)

Comparing performance of: toLowerCase() vs localeCompare() vs toLowerCase() FAIL vs localeCompare() FAIL vs toUpperCase() vs toUpperCase() FAIL

Created: 2 years ago by: Guest

Jump to the latest result

toLowerCase()

localeCompare()

toLowerCase() FAIL

localeCompare() FAIL

toUpperCase()

toUpperCase() FAIL

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):