Overview of the Benchmark

The provided JSON represents a JavaScript microbenchmark that measures the performance of different approaches to empty an array of 100,000 random numbers.

Benchmark Definition

The benchmark definition is as follows:

• Create an array of 100,000 random numbers using a for loop.
• Empty the array by one of four methods:
  • Instantiating a new array and assigning it to the original variable (var a1 = JSON.parse(json); a1 = [];)
  • Setting the length of the array to zero using the dot notation (var a2 = JSON.parse(json); a2.length = 0;)
  • Using splice to remove elements from the beginning of the array (var a3 = JSON.parse(json); a3.splice(0, a3.length);)
  • Looping through the array and popping each element using a while loop (var a4 = JSON.parse(json); while(a4.length > 0){a4.pop();})
• Compare the performance of these four methods.

Options Compared

The benchmark compares the performance of four different approaches to empty an array:

1. Instantiate new array: Create a new array and assign it to the original variable (var a1 = JSON.parse(json); a1 = [];)
2. Set length to zero: Set the length of the array to zero using the dot notation (var a2 = JSON.parse(json); a2.length = 0;)
3. Splice at index zero: Use splice to remove elements from the beginning of the array (var a3 = JSON.parse(json); a3.splice(0, a3.length);)
4. Pop all values: Loop through the array and pop each element using a while loop (var a4 = JSON.parse(json); while(a4.length > 0){a4.pop();})

Pros and Cons of Each Approach

• Instantiate new array: This approach creates a new array object, which can be slower than modifying the original array. However, it avoids the potential issues with modifying an array in place.
  • Pros: avoids modifying the original array, faster for some use cases
  • Cons: creates a new array object, may not be suitable for all use cases
• Set length to zero: This approach modifies the original array in place and is typically faster than creating a new array. However, it can lead to issues if the array contains references or other complex data structures.
  • Pros: fast, efficient, and easy to implement
  • Cons: may cause issues with modifying an array in place, requires caution when using references or complex data structures
• Splice at index zero: This approach uses splice to remove elements from the beginning of the array. It is similar to setting the length to zero but avoids the potential issues with modifying an array in place.
  • Pros: faster than creating a new array, easier to implement than setting the length to zero
  • Cons: may not be suitable for all use cases (e.g., if the array contains references or complex data structures)
• Pop all values: This approach loops through the array and pops each element using a while loop. It can lead to issues with modifying an array in place.
  • Pros: avoids modifying an array in place, may be suitable for certain use cases
  • Cons: slower than other approaches, may cause issues if the array contains references or complex data structures

Library Used

The benchmark uses JSON.parse to create a new JavaScript object from a JSON string. This is used as a baseline comparison for the four emptying methods.

Special JS Feature/Syntax

None of the benchmark test cases use special JS features or syntax that require additional explanation.

Other Alternatives

If you need to empty an array in JavaScript, consider using one of the following alternatives:

• Array.prototype.fill(): This method fills all elements of an array with a specified value. It can be used to clear an array by setting its length to zero.
• Array.prototype.slice(): This method creates a shallow copy of a portion of an array. It can be used to create a new array that contains the same elements as the original array, but it does not modify the original array.

In summary, the benchmark compares four different approaches to empty an array in JavaScript: instantiating a new array, setting the length to zero, using splice at index zero, and looping through the array and popping each element. Each approach has its pros and cons, and the choice of method depends on the specific use case and requirements.