Benchmark: Check empty an array in JavaScript?

Script Preparation code:

var size = 10000;
var arr1 = [];
for (var i = 0; i < size; i++){
  arr1.push(i);
}

Tests:

First Item
if(arr1[0]){ }
length>0
if(arr1.length>0){ }
!==0
if(arr1.length!==0){ }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
First Item
length>0
!==0

Fastest: N/A

Slowest: N/A

Latest run results:

No previous 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.

**Benchmark Overview**

The provided JSON represents a benchmark test for checking if an empty array in JavaScript is efficient. The benchmark defines two script preparation codes and one HTML preparation code, which are used to set up the testing environment. The individual test cases compare three different approaches: using the first item of the array (`arr1[0]`), checking the length of the array (`arr1.length>0`), and using the "not equal" operator (`arr1.length!==0`) to check if the array is not empty.

**Script Preparation Code**

The script preparation code is used to set up the testing environment. In this case, it creates an array `arr1` with 10,000 elements and pushes a value from 0 to 9 into each element using a `for` loop. This array will be used as input for the benchmark tests.

**Options Compared**

The three test cases compare the following options:

* **First Item (`arr1[0]`)**: This approach checks if the first item of the array is not empty (i.e., it's not null or undefined).
* **Length Check (`arr1.length>0`)**: This approach checks if the length of the array is greater than 0.
* **Not Equal Operator (`arr1.length!==0`)**: This approach uses the "not equal" operator to check if the length of the array is not equal to 0.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **First Item (`arr1[0]`)**:
	+ Pros: Simple and straightforward. It only checks one item in the array.
	+ Cons: May be slower than other approaches if the first item is null or undefined.
* **Length Check (`arr1.length>0`)**:
	+ Pros: Faster than checking individual items, as it uses a single operation to check the length of the array.
	+ Cons: May be slower for very large arrays, as it involves an additional operation.
* **Not Equal Operator (`arr1.length!==0`)**:
	+ Pros: Provides more accurate results, as it checks if the length is not equal to 0, which includes cases where the array is empty.
	+ Cons: Slower than the length check approach.

**Library and Special JS Features**

There are no libraries used in this benchmark. However, some special JavaScript features might be relevant:

* **Nullish Coalescing Operator (`??`)**: While not used directly in this benchmark, it's worth noting that some modern browsers support the nullish coalescing operator (`arr?.length ?? 0`). This operator is similar to the "not equal" operator but provides a more concise way to check if an expression has a truthy value.

**Other Alternatives**

Some alternative approaches to checking if an array is empty include:

* Using `Array.isArray()` and `!array.length`
* Using a custom function like `isEmpty(array) { return !array.length; }`

However, these alternatives may not be as efficient or concise as the "not equal" operator approach.

In summary, the benchmark test compares three different approaches to checking if an array is empty in JavaScript: using the first item of the array, checking the length of the array, and using the "not equal" operator. The choice of approach depends on the specific use case and performance requirements.

Related benchmarks:

Check empty an array in JavaScript? (version: 0)

Comparing performance of: First Item vs length>0 vs !==0

Created: 6 years ago by: Registered User

Jump to the latest result

First Item

length>0

!==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):