Benchmark: Javascript: Case insensitive string comparison performance

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)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_7 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.3 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 26 on iOS 18.7

View result in a separate tab

Test name	Executions per second
toLowerCase()	284492544.0 Ops/sec
localeCompare()	198610.0 Ops/sec
toLowerCase() FAIL	252288192.0 Ops/sec
localeCompare() FAIL	176212.4 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is crucial for optimizing and debugging code. Let's break down the provided benchmark definition and test cases to understand what's being tested.

**Benchmark Definition**

The benchmark measures the performance of case-insensitive string comparison using two approaches: `toLowerCase()` and `localeCompare()`. The script preparation code defines three strings with different casing (`John Doe`, `john doe`, and `john smith`) and an object with a single property, `sensitivity`, set to `'base'`.

**Test Cases**

There are four test cases:

1. `toLowerCase()`: Tests if the string comparison using `toLowerCase()` returns true for equal strings.
2. `localeCompare(b,undefined,o)`: Tests if the locale-aware string comparison using `localeCompare()` with default options (`b`, `undefined`, and an object with `sensitivity` set to `'base'`) returns true for equal strings.
3. `toLowerCase() FAIL`: This test case is similar to the first one but uses a different string (`john smith`). The purpose of this test case is likely to detect false positives where `toLowerCase()` might incorrectly return true due to the casing difference between `a` and `c`.
4. `localeCompare() FAIL`: Similar to the third test case, this test detects potential issues with locale-aware comparison.

**Options Compared**

Two main options are compared:

* `toLowerCase()`: A simple string normalization method that converts strings to lowercase.
* `localeCompare(b,undefined,o)`: A locale-aware string comparison method that takes into account regional differences in character ordering and casing.

**Pros and Cons of Each Approach**

1. **`toLowerCase()`**:
	* Pros: Simple, fast, and widely supported across browsers.
	* Cons: Loses original casing information, which might lead to unexpected behavior or false positives.
2. **`localeCompare(b,undefined,o)`**:
	* Pros: Preserves original casing information, takes into account regional differences, and is designed for locale-aware comparisons.
	* Cons: More complex, slower, and may have variations in performance across different browsers and locales.

**Library and Purpose**

The `localeCompare()` method uses the ECMAScript Internationalization API, which provides a way to compare strings in a locale-aware manner. The purpose of this method is to provide a standardized way of handling character ordering and casing differences across regions.

**Special JS Feature or Syntax**

None are explicitly mentioned in the provided benchmark definition.

**Other Alternatives**

While not tested in this specific benchmark, other alternatives for case-insensitive string comparison include:

* `normalize()` followed by `localeCompare()`
* Using a library like ICU (International Components for Unicode) for more precise locale-aware comparisons

Keep in mind that these alternatives might introduce additional complexity and performance overhead.

In summary, the benchmark tests two common approaches to case-insensitive string comparison: simple normalization using `toLowerCase()` versus locale-aware comparison using `localeCompare()`. By comparing the performance of these approaches, developers can choose the best solution for their specific use cases.

Related benchmarks:

Javascript: Case insensitive string comparison performance (version: 1)

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

Created: 5 years ago by: Registered User

Jump to the latest result

toLowerCase()

localeCompare()

toLowerCase() FAIL

localeCompare() FAIL

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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