Benchmark: pop vs index for array

Script Preparation code:


function popLast() {
  var arr = [0,1,2,3,4,5,6,7,8,9];
  const element = arr.pop();
  return element;
}

function indexLast() {
  var arr = [0,1,2,3,4,5,6,7,8,9];
  const element = arr[arr.lenght - 1];
  return element;
}

Tests:

pop check
popLast();
last-index check
indexLast();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
pop check
last-index check

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Linux

View result in a separate tab

Test name	Executions per second
pop check	58603360.0 Ops/sec
last-index check	36346192.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of MeasureThat.net and understand what's being tested in this benchmark.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that compares two approaches for accessing an element at the end of an array: the `pop` method and the last index check (`arr[arr.length - 1]`).

**Options compared**

Two options are being compared:

1. **Pop method**: The `pop` method removes and returns the last element from the array.
2. **Last index check**: This approach accesses the last element by using the array's length property minus one.

**Pros and Cons of each approach:**

* **Pop method**:
	+ Pros: Simple, efficient, and fast (since it doesn't require indexing).
	+ Cons: Modifies the original array, which might be a problem if the array is used elsewhere in the code.
* **Last index check**:
	+ Pros: Non-destructive, allowing the original array to remain unchanged.
	+ Cons: Requires accessing the `length` property of the array, which can be slower than the `pop` method.

**Library and its purpose**

In this benchmark, no external libraries are used. The script preparation code defines two functions (`popLast` and `indexLast`) that demonstrate the different approaches for accessing an element at the end of an array.

**Special JS feature or syntax**

None mentioned in this specific benchmark. However, it's worth noting that JavaScript arrays have undergone changes over time, such as with the introduction of `let`, `const`, and `arrow functions`. MeasureThat.net might be using a version of JavaScript that is older than some modern browsers.

**Other alternatives**

In theory, other approaches could be used to access an element at the end of an array:

1. Using `splice` or `concat`: Removing and re-indexing elements.
2. Accessing arrays by index directly (e.g., using a variable for the index).
3. Using other data structures, like linked lists or queues.

However, these alternatives might not be as efficient or straightforward as the `pop` method or last index check in this specific benchmark.

I hope this explanation helps you understand what's being tested in MeasureThat.net!

Related benchmarks:

pop vs index for array (version: 0)

Comparing pop method vs last index check for an array element

Comparing performance of: pop check vs last-index check

Created: one year ago by: Guest

Jump to the latest result

pop check

last-index check

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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