Benchmark: Test array reverse and pop vs shift

Tests:

reverse and pop
let arr = [1,2,3,4,5] arr.reverse() while(arr.length > 0) { arr.pop() }
shift
let arr = [1,2,3,4,5] while(arr.length > 0) { arr.shift() }

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

reverse and pop

43.7M/s

shift

17.3M/s

Fastest: reverse and pop (2.5x faster)

View exact numbers

✓ reverse and pop: 43,704,296 ops/sec
• shift: 17,309,238 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reverse and pop
shift

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Mac OS X 10.15.7

View result in a separate tab

reverse and pop

44.3M/s

shift

17.8M/s

View exact numbers

Test name	Executions per second
✓ reverse and pop	44,319,432 Ops/sec
shift	17,842,434 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the provided benchmark and its different test cases.

**Benchmark Overview**

The MeasureThat.net website allows users to create and run JavaScript microbenchmarks to compare the performance of different approaches. The provided benchmark is testing two ways to reverse an array and then pop elements from it, versus shifting elements from the end of the array.

**Test Cases**

There are two test cases:

1. **Reverse and Pop**: This test case uses the `reverse()` method to reverse the array and then pops elements from the reversed array using a while loop.
2. **Shift**: This test case uses a while loop to shift elements from the end of the original array.

**Library: Array.prototype.pop()**

The `pop()` method is used in both test cases, but it's worth noting that it modifies the original array and returns the last element. In the "Reverse and Pop" test case, the `reverse()` method is called first to reverse the array, and then the while loop pops elements from the reversed array.

**Library: Array.prototype.shift()**

The `shift()` method is used in the "Shift" test case. This method also modifies the original array and removes the first element.

**Special JS Feature/Syntax: None**

Neither of these test cases uses any special JavaScript features or syntax that would require additional explanation.

**Pros and Cons of Different Approaches**

Here's a brief summary of the pros and cons of each approach:

1. **Reverse and Pop**:
	* Pros:
		+ Can be more efficient for large arrays since it only modifies the original array.
		+ Can take advantage of browser optimizations for reversing an array.
	* Cons:
		+ Requires two extra operations: `reverse()` and `pop()`.
		+ May have additional overhead due to the while loop.
2. **Shift**:
	* Pros:
		+ Only requires one operation (the while loop).
		+ Does not require modifying the original array, which can be beneficial for large arrays.
	* Cons:
		+ Can be less efficient for small arrays since it creates a new array.
		+ May have additional overhead due to the while loop.

**Other Considerations**

When comparing these two approaches, it's essential to consider the following:

1. **Array size**: For larger arrays, the "Reverse and Pop" approach might be more efficient since it only modifies the original array.
2. **Browser optimizations**: Some browsers may optimize the `reverse()` method for reversing an array, which could affect the performance of the "Reverse and Pop" test case.
3. **Memory allocation**: The "Shift" test case creates a new array on each iteration, while the "Reverse and Pop" test case modifies the original array. This can impact memory allocation and deallocation.

**Alternatives**

Some alternative approaches you might consider:

1. **Using `Array.prototype.slice()` to create a copy of the array**: Instead of using `pop()` or `shift()`, you could use `slice()` to create a new array with only the desired elements.
2. **Using `for...of` loops instead of while loops**: Using `for...of` loops can simplify the code and reduce overhead compared to traditional while loops.

Keep in mind that these alternatives may have different performance characteristics, so it's essential to test them thoroughly to determine the best approach for your specific use case.

Test array reverse and pop vs shift (version: 0) Benchmark.js

Comparing performance of: `reverse and pop vs shift`

Created: 2 years ago by: Guest

Go to the latest result

reverse and pop

shift

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Test array reverse and pop vs shift (version: 0) Benchmark.js

Comparing performance of: reverse and pop vs shift

Created: 2 years ago by: Guest

Go to the latest result

reverse and pop

shift

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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Comparing performance of: `reverse and pop vs shift`