Benchmark: Array empty - MeasureThat.net

Script Preparation code:

arr = []

Tests:

length == 0
if(arr.length == 0) {console.log("!")}
arr == []
if(arr == []) {console.log("!")}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
length == 0
arr == []

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the benchmark and its test cases.

**What is being tested?**

The provided benchmark tests two different ways to check if an array is empty in JavaScript: using the `length` property or using the `==` operator with the array literal syntax (`[]`). The goal is to measure which approach is faster.

**Options compared**

There are two options being compared:

1. **Using `length`**: This method checks the length of the array, which is a built-in property in JavaScript. It returns `0` if the array is empty.
2. **Using `== []`**: This method checks if the array is equal to an empty array (`[]`). This is a common way to check for emptiness in arrays.

**Pros and Cons**

1. **Using `length`**:
	* Pros: Fast, reliable, and widely supported.
	* Cons: May not work as expected if `length` is used outside of arrays (e.g., with objects).
2. **Using `== []`**:
	* Pros: Simple and readable code.
	* Cons: Can be slower than using `length`, especially for large arrays, since it involves creating a new array object and comparing it.

**Library usage**

There is no library explicitly mentioned in the benchmark definition or test cases. However, note that the use of `== []` might trigger the implementation of some JavaScript engines to create an empty array object, which could potentially introduce additional overhead.

**Special JS feature or syntax**

None are mentioned explicitly, but it's worth noting that the use of `== []` is a common pattern in JavaScript. The expression `arr == []` is a shorthand way to check if an array is empty.

**Other alternatives**

If you wanted to test other approaches for checking if an array is empty, you might consider:

1. **Using a custom function**: You could define a custom function that checks the length or uses a more complex algorithm to determine emptiness.
2. **Using `Array.isArray()`**: This method returns `true` if the input is an array and `false` otherwise. You could use this to check if an array is empty by comparing it to `null`.
3. **Using a loop**: You could write a loop that checks each element of the array, incrementing a counter until it finds a non-empty element or reaches the end of the array.

Here's some sample benchmarking code using Node.js and the ` Benchmark` library:
```javascript
const Benchmark = require('benchmark');

// Custom function to check if an array is empty
function isEmpty(arr) {
  return arr.length === 0;
}

// Using length
function testLength() {
  const arr = [];
  if (arr.length == 0) {
    console.log("!");
  }
}

// Using ==
function testEquals() {
  const arr = [];
  if (arr == []) {
    console.log("!");
  }
}

// Custom function using Array.isArray()
function testArrayIsArray() {
  const arr = [];
  if (!Array.isArray(arr)) {
    throw new Error('Not an array');
  }
}

// Loop through each element
function testLoop() {
  const arr = [];
  for (const elem of arr) {
    // do nothing
  }
}

const suite = Benchmark.Suite;

suite.add('length', testLength);
suite.add('==', testEquals);
suite.add('Array.isArray()', testArrayIsArray);
suite.add('loop', testLoop);

suite.on('complete', function() {
  console.log('Done');
});

suite.run();
```
Note that this is just one possible way to write a benchmarking test. You may want to experiment with different approaches and optimization techniques to find the best solution for your specific use case.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/79.0.3945.79 Chrome/79.0.3945.79 Safari/537.36

Browser/OS: Chromium 79 on Ubuntu

View result in a separate tab

Test name	Executions per second
length == 0	78546.2 Ops/sec
arr == []	5347035.5 Ops/sec

Related benchmarks:

Array empty (version: 0)

Comparing performance of: length == 0 vs arr == []

Created: 4 years ago by: Guest

Jump to the latest result

length == 0

arr == []

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):