Benchmark: length vs length > 0

Script Preparation code:

var arr = [1,2,3];

Tests:

arr.length
if (arr.length) {}
arr.length > 0
if (arr.length > 0) {}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
arr.length
arr.length > 0

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
arr.length	20732336.0 Ops/sec
arr.length > 0	21966086.0 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 and explain what's being tested.

**Benchmark Definition JSON**

The provided JSON defines a benchmark with two test cases:

* `length vs length > 0`: This is the name of the benchmark, which suggests that it's testing the performance difference between checking if an array has a certain property (`length`) versus checking if that property is greater than zero (`length > 0`).
* `Script Preparation Code`: This specifies the code that should be executed before running each test case. In this case, it initializes an array variable `arr` with three elements.
* `Html Preparation Code`: This is empty, which means no HTML preparation code is needed for this benchmark.

**Individual Test Cases**

The benchmark has two individual test cases:

1. `if (arr.length) {}`
2. `if (arr.length > 0) {}

These test cases are testing the performance of checking if the `length` property of the `arr` array is truthy (`true`), and the performance of checking if it's greater than zero (`false`) respectively.

**Library Used**

The benchmark uses the built-in JavaScript `Array` object, specifically its `length` property. The `Array` object is a fundamental part of the JavaScript language and provides various methods for manipulating and accessing array elements.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntax being used in this benchmark. It's standard JavaScript code that leverages the built-in `Array` object.

**Pros and Cons of Different Approaches**

In general, checking if an array has a certain property like `length` is more efficient than checking if it's greater than zero because:

* Checking `arr.length > 0` involves additional operations:
	+ Creating an expression that compares two values.
	+ Evaluating the comparison to determine the result (either `true` or `false`).
	+ Returning one of these boolean values.

In contrast, simply checking `arr.length` is a simpler operation:

* It's a single property access on the array object.
* It returns either a number value (the length of the array) or `undefined` if the array is empty.

**Other Alternatives**

If you want to benchmark similar operations, consider testing other scenarios, such as:

* Checking if an element exists in an array using `arr.includes()`.
* Creating and searching for an object in an array using `Object.prototype.indexOf()` or a modern alternative like `Array.prototype.findIndex()`.
* Using a custom function to check the length of an array.

Keep in mind that these alternatives might introduce additional complexity, so it's essential to tailor your benchmarking approach to the specific use case you're trying to measure.

Related benchmarks:

length vs length > 0 (version: 0)

Comparing performance of: arr.length vs arr.length > 0

Created: 6 years ago by: Guest

Jump to the latest result

arr.length

arr.length > 0

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):