Overview

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided JSON represents a benchmark for creating a 2D square array filled with arrays of the same length.

Benchmark Definition

The benchmark definition consists of two parts:

1. Script Preparation Code: This code sets up the environment for the test. In this case, it simply declares a variable size and assigns it a value of 15.
2. Html Preparation Code: There is no HTML preparation code provided.

Individual Test Cases

There are six individual test cases that compare different approaches to creating a 2D square array:

1. While Loop with Declaration

let index = array.length;
while (index-- > 0) {
  const temp = [];
  temp.length = size;
  array[index] = temp;
}

This approach uses a while loop to create each inner array and assigns it to the corresponding index in the outer array.

2. While Loop with Slice

let index = array.length;
while (index-- > 0) {
  const temp = [];
  temp.length = size;
  array[index] = temp.slice(0);
}

This approach uses a while loop to create each inner array, and then slices the newly created array to assign it to the corresponding index in the outer array.

3. While Loop with Push and Slice

let index = size;
while (index-- > 0) {
  const temp = [];
  temp.length = size;
  array.push(temp.slice(0));
}

This approach uses a while loop to create each inner array, slices the newly created array, and then pushes it onto the outer array using push.

4. While Loop with Push

let index = size;
while (index-- > 0) {
  const temp = [];
  temp.length = size;
  array.push(temp);
}

This approach uses a while loop to create each inner array and pushes it onto the outer array using push.

5. Array.from with map

const array = Array.from(Array(size), () => {
  const temp = [];
  temp.length = size;
  return temp;
});

This approach uses Array.from() to create an array of inner arrays, where each inner array is created using the provided callback function.

6. Array.from with map and slice

const array = Array.from(temp, () => temp.slice());

This approach uses Array.from() to create an array of inner arrays, but instead of creating a new array for each iteration, it reuses the existing temp array by slicing it.

Options Compared

The benchmark compares six different approaches to creating a 2D square array:

• While Loop with Declaration
• While Loop with Slice
• While Loop with Push and Slice
• While Loop with Push
• Array.from with map
• Array.from with map and slice

Each approach has its own pros and cons:

Pros and Cons

1. While Loop with Declaration
   • Pros: Simple, easy to understand.
   • Cons: May be slower due to the overhead of incrementing a variable.
2. While Loop with Slice
   • Pros: Reuses the existing array for each iteration, potentially faster.
   • Cons: Requires an additional function call (slice()).
3. While Loop with Push and Slice
   • Pros: Simple, easy to understand.
   • Cons: May be slower due to the overhead of pushing elements onto an array.
4. While Loop with Push
   • Pros: Fast, efficient.
   • Cons: More complex, requires understanding of array manipulation.
5. Array.from with map
   • Pros: Fast, efficient, easy to understand.
   • Cons: Requires Array.from() and a callback function.
6. Array.from with map and slice
   • Pros: Reuses the existing array for each iteration, potentially faster.
   • Cons: More complex, requires understanding of array manipulation.

Conclusion

The benchmark provides insight into the performance characteristics of different approaches to creating a 2D square array in JavaScript. While Loop with Push appears to be the fastest approach, it also has the most complex logic. The Array.from() methods provide a good balance between performance and simplicity. Ultimately, the choice of approach depends on personal preference, coding style, and specific use case requirements.