Benchmark: JavaScript with - MeasureThat.net

Script Preparation code:

array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

Tests:

array.with(1, "newUser");
array[1] = "newUser";
Array.toReversed()
array.toReversed();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.with(1, "newUser");
Array.toReversed()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 11 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0

Browser/OS: Firefox 138 on Windows

View result in a separate tab

Test name	Executions per second
array.with(1, "newUser");	528332256.0 Ops/sec
Array.toReversed()	17426220.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 11 months ago):

LLMs can make mistakes. Check important info.

The benchmark you provided is focused on comparing the performance of different methods of manipulating arrays in JavaScript. Specifically, it evaluates two individual test cases in relation to an initial array setup.

### What is Tested 
1. **Inline Array Mutation**: The first test case modifies an element in the array directly.
   - **Test Case**: `"array[1] = \"newUser\";"`
   - **Test Name**: `array.with(1, "newUser");`

2. **Array Reversal**: The second test case uses a built-in array method to reverse the elements of the array.
   - **Test Case**: `"array.toReversed();"`
   - **Test Name**: `Array.toReversed()`

### Options Compared
- **Direct Index Modification** (`array[1] = "newUser";`)
  - This operation directly accesses the second element of the array and assigns a new value to it. 
- **Using the `Array.toReversed()` Method**
  - This method creates a new array that is a reversed version of the original array, leaving the original array unchanged.

### Pros and Cons

#### Direct Index Modification (`array[1] = "newUser";`)
- **Pros**:
  - Simple syntax and very performant when modifying a single element.
  - Directly changes the existing array without needing to allocate additional memory for a new array.

- **Cons**:
  - Less expressive than method calls; may not convey intentions as clearly in more complex manipulations.
  - Not suitable if you want to perform reversible operations or if you intend to maintain the initial array's order without altering it.

#### Using `Array.toReversed()`
- **Pros**:
  - Semantically clear for someone reading the code; it explicitly states the intention to reverse the array.
  - Does not mutate the original array, which may be beneficial in functional programming paradigms or when immutability is preferred.

- **Cons**:
  - Potentially less performant than direct mutation, especially for large arrays, as it involves creating a new array and copying elements.
  - Requires more memory to hold the new, reversed array.

### Other Considerations
- **Performance Metrics**: The benchmark results indicate the executions per second for each method. `array.with(1, "newUser");` achieved 528,332,256 executions per second compared to `Array.toReversed()`, which achieved 17,426,220 executions per second. This highlights the significant performance advantage of direct mutation over method calls that create new arrays.
  
- **Using Newer JavaScript Features**: The `Array.toReversed()` method is part of newer specifications (ES2022) and may not be supported in older JavaScript environments. This is an important consideration regarding browser compatibility, as seen in the user-agent string indicating the use of Firefox 138.

### Alternatives
- **Alternative Methods for Array Mutation**:
  - Other ways to modify an element could include using functional programming methods like `map()` or `slice()`, though these would not be as direct or efficient for updating individual array items.
  
- **Alternative Reversal Techniques**:
  - One could manually reverse an array using loops, `reduce()`, or other methods, but these are generally less concise and could be less efficient than the built-in `toReversed()` method.

In essence, this benchmark helps developers understand the performance implications of different methods of array manipulation in JavaScript and evaluate which method to use based on their specific use case and performance requirements.

Related benchmarks:

JavaScript with (version: 1)

Compare With to inline array mutation

Comparing performance of: array.with(1, "newUser"); vs Array.toReversed()

Created: 11 months ago by: Guest

Jump to the latest result

array.with(1, "newUser");

Array.toReversed()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 11 months ago):