Benchmark: Iterate array backwards then clear

Tests:

array.length = 0
let size = 10000 let arr = [] for (let i = 0; i < size; i++){ arr.push(i) } let sum = 0 for (let i = arr.length; --i >= 0; ) { sum += arr[i] } arr.length = 0
array.pop()
let size = 10000 let arr = [] for (let i = 0; i < size; i++){ arr.push(i) } let sum = 0 for (let v; (v = arr.pop()); ) { sum += v }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.length = 0
array.pop()

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36

Browser/OS: Chrome 115 on Windows

View result in a separate tab

Test name	Executions per second
array.length = 0	9707.1 Ops/sec
array.pop()	8728.9 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the benchmark and explain what's being tested.

**Benchmark Overview**

The MeasureThat.net website allows users to create and run JavaScript microbenchmarks. The provided JSON represents a benchmark definition and two individual test cases.

**What is Tested?**

The benchmark tests two different approaches for iterating over an array in reverse order, clearing the array, and calculating a sum:

1.  **Approach 1: Using `arr.length`** (`"array.length = 0"` test case)

*   In this approach, the array is filled with 10,000 elements using a traditional `for` loop.
    *   Then, the code iterates over the array in reverse order using another `for` loop, summing up the values.
    *   After iterating over the entire array, the `arr.length` property is set to 0.

2.  **Approach 2: Using `Array.pop()`** (`"array.pop()"` test case)

*   In this approach, the same array is filled with 10,000 elements using a traditional `for` loop.
    *   Then, the code iterates over the array in reverse order by repeatedly calling `arr.pop()`, summing up the values.

**Options Compared**

The two approaches are compared to determine which one performs better in terms of execution speed.

**Pros and Cons of Each Approach:**

*   **Using `arr.length`**
    *   Pros:
        *   More straightforward and easier to understand.
        *   Does not require knowledge of array methods or special behavior when popping elements from the end.
    *   Cons:
        *   May involve more overhead due to repeated property access (`arr.length`).
*   **Using `Array.pop()`**
    *   Pros:
        *   Can be faster because it eliminates the need for explicit loop counters and reduces memory allocations.
        *   More concise and expressive code, leveraging native array methods.
    *   Cons:
        *   Requires knowledge of array methods and special behavior when popping elements from the end.

**Library Used:**

None explicitly mentioned in the provided benchmark definition. However, it's likely that MeasureThat.net uses a JavaScript engine or runtime environment (e.g., V8) that provides a standardized way to execute and measure JavaScript code.

**Special JS Feature/Syntax:**

The `for...of` loop is not used in either test case. It would require an alternative approach if you wanted to use it for iterating over the array elements.

Related benchmarks:

Iterate array backwards then clear (version: 1)

Comparing performance of: array.length = 0 vs array.pop()

Created: one year ago by: Registered User

Jump to the latest result

array.length = 0

array.pop()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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