Benchmark: Compare !array.length vs array.length === 0

Script Preparation code:

var arr = [];

Tests:

!array.length
if (!arr.length) { console.log(1); } else { console.log(0); }
arr.length === 0
if (arr.length === 0) { console.log(1); } else { console.log(0); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
!array.length
arr.length === 0

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36 Edg/132.0.0.0

Browser/OS: Chrome 132 on Windows

View result in a separate tab

Test name	Executions per second
!array.length	155163.9 Ops/sec
arr.length === 0	157398.7 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and benchmark preparation code to understand what is being tested.

**What is being tested?**

The test is comparing two ways of testing an empty array:

1. `!array.length` (using the negation operator)
2. `array.length === 0` (using a direct comparison with zero)

In essence, the test is checking which approach is faster and more efficient.

**Options compared:**

* Negation operator (`!`) vs direct comparison with zero (`===`)
* Two different syntaxes for testing an empty array

**Pros and Cons of each approach:**

1. **Negation operator (`!`)**:
	* Pros: Simple, concise, and easy to read.
	* Cons: May be slower due to the extra operation required to negate the value. In modern JavaScript engines, this difference is likely negligible, but it's still a consideration.
2. **Direct comparison with zero (`===`)**:
	* Pros: Faster in some cases (e.g., when using the `===` operator for equality checks), as it can take advantage of the browser's optimization for direct comparisons.
	* Cons: May be more verbose and harder to read than the negation operator.

**Library and special JS feature used:**

None are mentioned in this specific benchmark. However, some libraries or frameworks might use these syntaxes differently or provide alternative ways of testing empty arrays.

**Special JS feature explained (if applicable):**

In modern JavaScript, the `===` operator is used for strict equality comparisons. This means that it will perform a type check before comparing values, which can be beneficial in certain situations. The negation operator (`!`) is often used to simplify conditional statements and avoid repetition.

**Other alternatives:**

For testing empty arrays, other approaches could include:

* Using the `isEmpty()` method provided by some libraries or frameworks.
* Checking if an array has at least one element using `array.length > 0`.
* Using a library like Lodash's `isEmpty` function.

However, these alternatives might not be relevant to this specific benchmark, as it focuses on comparing two simple syntaxes for testing empty arrays.

Related benchmarks:

Compare !array.length vs array.length === 0 (version: 0)

Compare both ways of test an empty array

Comparing performance of: !array.length vs arr.length === 0

Created: one year ago by: Guest

Jump to the latest result

!array.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 6 months ago):