Benchmark: ToLower vs ToUpper

Script Preparation code:

var data = []

for (let i = 0; i < 5000; ++i) data.push('toto')
data.push('titi')
for (let i = 0; i < 2500; ++i) data.push('toto')

Tests:

ToUpper
data.map(d => d.toUpperCase())
ToLower
data.map(d => d.toLowerCase())

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

ToLower

16K/s

ToUpper

5K/s

Fastest: ToLower (3.1x faster)

View exact numbers

✓ ToLower: 16,459 ops/sec
• ToUpper: 5,264 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
ToUpper
ToLower

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

ToLower

23K/s

ToUpper

7K/s

View exact numbers

Test name	Executions per second
✓ ToLower	22,939 Ops/sec
ToUpper	7,396 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is an essential task for developers, and tools like MeasureThat.net help make it easier.

The provided JSON represents a benchmark that compares the performance of two JavaScript methods: `toUpperCase()` and `toLowerCase()`. The test case uses an array `data` containing 7500 elements, which are pushed with the strings "toto" and "titi".

Let's break down what options are compared:

1. **ToUpper** (using `toUpperCase()`): This option tests the performance of the `toUpperCase()` method when applied to the entire array.
2. **ToLower** (using `toLowerCase()`): This option tests the performance of the `toLowerCase()` method when applied to the entire array.

Now, let's discuss the pros and cons of these approaches:

*   **ToUpper**: The `toUpperCase()` method is likely to be faster because it only involves a single character conversion operation. However, this approach may not work well for large arrays containing non-ASCII characters or special characters.
*   **ToLower**: The `toLowerCase()` method can be slower than `toUpperCase()` due to the additional processing required to convert uppercase letters to lowercase. Nevertheless, modern JavaScript engines have optimized these methods for better performance.

Other considerations:

*   **Character Encoding**: When working with arrays containing non-ASCII characters or special characters, you may need to consider character encoding when using these methods.
*   **Loop Iteration**: If the array is very large and you want to avoid excessive memory allocation, iterating over the array using a loop instead of the `map()` method can be beneficial.

Now, let's move on to library usage. In this case, no libraries are explicitly mentioned in the provided JSON.

If special JavaScript features or syntax were used, it would mean that there is some specific code optimization technique being tested. Unfortunately, none of these techniques are present here.

One alternative approach could be running the `toUpperCase()` and `toLowerCase()` methods on a smaller test array to see which one performs better for small datasets before scaling up to larger arrays.

Another alternative method is to add error checking to ensure that no character conversions fail in the data; it can make code cleaner, easier to debug and more flexible

ToLower vs ToUpper (version: 0) Benchmark.js

Comparing performance of: `ToUpper vs ToLower`

Created: 5 years ago by: Guest

Go to the latest result

ToUpper

ToLower

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

ToLower vs ToUpper (version: 0) Benchmark.js

Comparing performance of: ToUpper vs ToLower

Created: 5 years ago by: Guest

Go to the latest result

ToUpper

ToLower

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Comparing performance of: `ToUpper vs ToLower`