Benchmark: check if array is empty or not using length and at method

Script Preparation code:

var arr = [1, 2, 3, 4]

Tests:

check using length
var d = arr.length ===0
check using at() method
var z = arr.at(-1)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
check using length
check using at() method

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/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Windows

View result in a separate tab

Test name	Executions per second
check using length	13901081.0 Ops/sec
check using at() method	13914380.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark definition and test cases.

**Benchmark Definition**

The benchmark measures whether JavaScript engines can efficiently determine if an array is empty or not using two different approaches: `length` and `at()` methods.

**Options Compared**

Two options are compared:

1. **Using `length`**: This method checks if the length of the array is 0, which indicates that the array is empty.
2. **Using `at(-1)`**: This method uses the `at()` function to access the last element of the array (index -1). If the result is undefined or null, it means the array is empty.

**Pros and Cons**

* **Using `length`**:
	+ Pros: Simple and widely supported by most JavaScript engines.
	+ Cons: May be slower for large arrays due to the need to calculate the length.
* **Using `at(-1)`**:
	+ Pros: Can be faster than using `length` since it only needs to access a single element, even if the array is empty.
	+ Cons: Requires support for the `at()` function in the JavaScript engine, which might not be available or supported equally by all engines.

**Library**

None of these test cases use any external libraries. They rely on built-in JavaScript features.

**Special JS Feature or Syntax**

The `at()` function is a relatively new addition to the JavaScript standard library (ECMAScript 2022). It allows accessing elements in an array without having to specify their indices, but also introduces some performance considerations, as explained above.

**Other Alternatives**

If the `at()` function is not supported or optimized by your target JavaScript engine, you can use alternative methods:

1. **Using `length`**: As mentioned earlier.
2. **Checking for undefined**: Use a conditional statement to check if the result of `arr.at(-1)` is `undefined`: `if (arr.at(-1) === undefined) { ... }`

Keep in mind that these alternatives might not be as efficient or optimized as using the `at()` function directly.

**Benchmark Preparation Code**

The script preparation code provided creates a sample array with 4 elements: `[1, 2, 3, 4]`.

**Individual Test Cases**

These test cases perform two separate checks:

1. **Using `length`**: Verifies that the length of the array is 0.
2. **Using `at(-1)`**: Uses the `at()` function to access the last element of the array and verifies that it returns `undefined`, indicating an empty array.

By comparing these two approaches, MeasureThat.net can provide insights into how different JavaScript engines optimize performance for array checks.

Related benchmarks:

check if array is empty or not using length and at method (version: 0)

Comparing performance of: check using length vs check using at() method

Created: one year ago by: Guest

Jump to the latest result

check using length

check using at() method

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):