Let's break down the provided benchmark and its results.

Benchmark Definition

The benchmark definition represents a JavaScript code snippet that clones an array of arrays, where each inner array has 100 elements with values generated by multiplying the row index (r) by 100 and adding the column index (c). The goal is to measure how fast different approaches can create a copy of this large two-dimensional array.

Script Preparation Code

The script preparation code creates the original array original and populates it with data:

var original = new Array(100);
for (let r = 0; r < 100; r++) {
  original[r] = [];
  for (let c = 0; c < 100; c++) {
    original[r][c] = r * 100 + c;
  }
}

This code is executed before running the test cases.

Html Preparation Code

The html preparation code is empty, which means it doesn't perform any additional setup or preparation for the benchmark.

Individual Test Cases

There are two test cases:

1. splice

var copy = new Array(original.length);
for (let r = 0; r < original.length; r++) {
  copy[r] = original[r].splice(0);
}

This approach uses Array.prototype.splice() to remove the first element from each inner array and assign the result to a new array. The copy variable will contain the cloned data.

2. map

var copy = original.map(row => row.splice(0));

This approach uses the Array.prototype.map() method with a callback function that removes the first element from each inner array and returns the result. The copy variable will contain the cloned data.

Benchmark Results

The latest benchmark results show the performance of both test cases:

1. map

"ExecutionsPerSecond": 362622.0,

This approach executes approximately 362,622 times per second on a Mac with Yandex Browser 24 and Mac OS X 10.15.7.

2. splice

"ExecutionsPerSecond": 64149.359375,

This approach executes approximately 64,149 executions per second on the same machine.

Comparison of Approaches

Here's a brief comparison of the two approaches:

1. map(): This approach is generally faster because it uses a more efficient algorithm that avoids iterating over the inner arrays multiple times.
2. splice(): This approach is slower due to the overhead of calling Array.prototype.splice() and modifying the original array.

Pros and Cons

Pros of map():

• Faster execution
• Less memory allocation and deallocation

Cons of map():

• May require additional memory for the callback function's scope
• May not be as readable or maintainable due to the use of a callback function

Pros of splice():

• More control over the cloning process
• Can be more readable if using a custom implementation

Cons of splice():

• Slower execution
• More memory allocation and deallocation

Alternative Approaches

Some alternative approaches for cloning arrays in JavaScript include:

1. Array.prototype.slice(): This method creates a shallow copy of an array, which may not work well for 2D arrays.

var copy = original.map(row => row.slice());

2. Array.prototype.reduce(): This method can be used to create a deep copy of an array by reducing the inner arrays to their first elements.

var copy = original.map(row => row.reduce((a, b) => [b], [])[0]);

3. libya.array.clone(): This is a utility function that creates a deep clone of an array.

const { cloneArray } = require('libya.array');
var copy = cloneArray(original);

Note: These alternative approaches may have different trade-offs in terms of performance, memory usage, and readability.