Benchmark: Uppercase - MeasureThat.net

Tests:

Split
"lorem ipsum".split('').map((char, index) => index % 2 ? char.toUpperCase() : char).join('');
replace
"lorem ipsum".replace(/(.)(.)/g, (substring, m1, m2) => { return m1 + m2.toUpperCase(); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Split
replace

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases.

**What is being tested?**

The primary purpose of this benchmark is to measure the performance difference between two JavaScript functions: `split()` and `replace()`. The tests are designed to process a string containing the Latin phrase "lorem ipsum".

**Options compared:**

There are two options being compared:

1. **`split()`**: This method splits a string into an array of substrings based on a specified separator (in this case, no separator is provided, so it defaults to splitting on whitespace). The `map()` function is then used to apply a transformation to each substring.
2. **`replace()`**: This method replaces all occurrences of a pattern in a string with a replacement value.

**Pros and Cons:**

**`split()`**

Pros:

* Easy to understand and implement
* Fast, as it only requires iterating over the characters of the input string

Cons:

* May be slower than `replace()` for large input strings due to the overhead of creating an array from the split substrings
* Requires more memory, as a new array needs to be created

**`replace()`**

Pros:

* Can be faster and more efficient for large input strings, as it only requires searching for patterns in the string
* Does not require creating a temporary array

Cons:

* May have a higher overhead due to the complexity of regular expression matching
* Less straightforward to understand and implement than `split()`

**Library and purpose:**

In the provided benchmark definition, there is no explicit mention of any JavaScript library. However, it's worth noting that the use of `.map()` in both test cases implies that a modern JavaScript environment (likely with a recent version of ECMAScript) is being used.

**Special JS feature or syntax:**

There are no special JavaScript features or syntax mentioned in this benchmark. The focus is on comparing two built-in methods (`split()` and `replace()`) for performance purposes.

**Other alternatives:**

If you want to test alternative approaches, here are a few possibilities:

1. Using a custom implementation of the `.split()` method (e.g., using a simple loop instead of the Array.prototype implementation)
2. Using a regular expression with the `g` flag (instead of the string-based matching in the `replace()` example)

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36

Browser/OS: Chrome 85 on Windows

View result in a separate tab

Test name	Executions per second
Split	839289.4 Ops/sec
replace	377312.2 Ops/sec

Related benchmarks:

Uppercase (version: 0)

Comparing performance of: Split vs replace

Created: 4 years ago by: Guest

Jump to the latest result

Split

replace

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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