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

Script Preparation code:

var arr = [];

Tests:

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

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The provided JSON represents two test cases for comparing the performance of two different approaches to check if an array `arr` has a length greater than 0.

**Options compared:**

1. **`!arr.length`**: This approach uses the logical NOT operator (`!`) to negate the result of `arr.length`. It returns `true` if `arr.length` is 0, and `false` otherwise.
2. **`arr.length === 0`**: This approach directly compares the length of `arr` with 0 using the strict equality operator (`===`). It returns `true` only if `arr.length` is exactly 0.

**Pros and Cons:**

1. **`!arr.length`**:
	* Pros:
		+ May be faster due to optimization by some JavaScript engines.
		+ Can be a good option when you want to check if an array is empty quickly, but it may not be immediately clear what the code does without additional context.
	* Cons:
		+ May be less readable and maintainable for developers who are not familiar with this syntax.
		+ Can lead to unexpected behavior if used incorrectly.
2. **`arr.length === 0`**:
	* Pros:
		+ More readable and maintainable, as it directly conveys the intent of checking if an array is empty.
		+ Less likely to lead to unexpected behavior.
	* Cons:
		+ May be slower due to the comparison operation.

**Library usage:**

None mentioned in this specific benchmark definition. However, some libraries like Lodash or Ramda may provide similar functions for working with arrays, such as `isEmpty()` or `isNil()`, which could potentially affect the performance of these tests.

**Special JS feature or syntax:**

The use of the logical NOT operator (`!`) to negate a value is not specific to any particular JavaScript version. However, it's worth noting that this syntax was introduced in ECMAScript 2015 (ES6) as part of the new arithmetic operators.

**Other alternatives:**

For testing array length checks, you might also consider using:

1. `arr.length > 0`: This approach is similar to `arr.length === 0` but uses a greater-than operator instead.
2. `!arr.includes(0)`: This approach uses the `includes()` method to check if the array does not contain the value 0, which can be equivalent to checking for an empty array.

These alternatives may offer different trade-offs in terms of performance, readability, and maintainability, depending on your specific use case.

Related benchmarks:

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

Comparing performance of: array length vs array length > 0

Created: 3 years ago by: Guest

Jump to the latest result

array length

array length > 0

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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