Benchmark: Filtering out empty rows from a 2D Array

Script Preparation code:

// Array with alternating empty and non-empty arrays
const arraySize = 1000;
var testArray = new Array(arraySize)
    .fill(null)
    .map((_, i) => i % 2 === 0
        // Make the values alternate between 0-2
        ? new Array(i).fill(0).map((_, j) => j % 2) 
        : []);

function doubleNegateLength({ length }) {
 return !!length; 
}

function lengthGreaterThanZero({ length }) {
  return length > 0;
}

function doubleNegate(value) {
  return !!value;
}

var booleanConstructor = Boolean;

Tests:

Double negation (!!row.length)
testArray.filter(doubleNegateLength);
Comparison (row.length > 0)
testArray.filter(lengthGreaterThanZero);
Double negation (!!row)
testArray.filter(doubleNegate);
Boolean constructor
testArray.filter(booleanConstructor);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Double negation (!!row.length)
Comparison (row.length > 0)
Double negation (!!row)
Boolean constructor

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
Double negation (!!row.length)	153157.4 Ops/sec
Comparison (row.length > 0)	150694.2 Ops/sec
Double negation (!!row)	115213.0 Ops/sec
Boolean constructor	124618.1 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 10 days ago):

LLMs can make mistakes. Check important info.

The benchmark conducted on MeasureThat.net evaluates different approaches for filtering out empty rows from a two-dimensional array in JavaScript. The focus is on the performance of various methods employed to check for truthiness or non-emptiness of elements in an array. Below is a detailed analysis of the different test cases, their pros and cons, and additional considerations.

### Test Cases Explained

1. **Double Negation of Length (`!!row.length`)**:
   - **Benchmark Definition**: `testArray.filter(doubleNegateLength);`
   - **Test Name**: "Double negation (!!row.length)"
   - **Description**: This approach checks if the length of each row is truthy (greater than zero) by applying double negation.
   - **Pros**: 
     - Clear and explicit method for checking non-emptiness.
     - Performance is often good due to direct property access.
   - **Cons**: 
     - Might be seen as less intuitive for those unfamiliar with the double negation idiom in JavaScript.

2. **Comparison with Greater Than Zero (`row.length > 0`)**:
   - **Benchmark Definition**: `testArray.filter(lengthGreaterThanZero);`
   - **Test Name**: "Comparison (row.length > 0)"
   - **Description**: This method uses a direct comparison operator to determine if the length of each row is greater than zero.
   - **Pros**: 
     - Straightforward and easy to understand.
     - Familiar comparison operator.
   - **Cons**: 
     - Generally very similar performance to double negation, but may be slightly slower due to the need for comparison operator evaluation.

3. **Double Negation on Row (`!!row`)**:
   - **Benchmark Definition**: `testArray.filter(doubleNegate);`
   - **Test Name**: "Double negation (!!row)"
   - **Description**: Uses double negation to check if the row itself is truthy.
   - **Pros**: 
     - Simple syntax and quick evaluation for truthy/falsy value.
   - **Cons**: 
     - Potential ambiguity since it checks the row object directly, which could be misleading if the intention is to check for empty arrays specifically.

4. **Boolean Constructor**:
   - **Benchmark Definition**: `testArray.filter(booleanConstructor);`
   - **Test Name**: "Boolean constructor"
   - **Description**: Uses the `Boolean` constructor to test the truthiness of the row.
   - **Pros**: 
     - Clear intention to convert the value to a Boolean.
   - **Cons**: 
     - Generally the slowest of the methods as it incurs additional overhead for creating a new Boolean object.

### Performance Results

Based on the latest benchmark results, the execution speeds (executions per second) were measured as follows:

- **Double negation on length (`!!row.length`)**: **153,157** executions/sec (fastest)
- **Comparison with greater than zero (`row.length > 0`)**: **150,694** executions/sec
- **Boolean constructor**: **124,618** executions/sec
- **Double negation on row (`!!row`)**: **115,213** executions/sec (slowest)

### Additional Considerations

- **Performance Implications**: When working with large datasets, the choice of filtering method can have substantial implications on performance, especially with repetitive tasks. The double negation on length is typically the fastest, making it preferable in performance-critical scenarios.
  
- **Readability vs. Performance**: It's important to balance performance and code readability. While certain methods may be faster, others may be clearer, especially for teams with varying levels of experience in JavaScript.

### Alternatives

- **Array.prototype.reduce**: Another strategy to filter arrays is using `reduce()`, which may be less efficient than `filter()`, especially for large arrays. It allows custom accumulation logic, but for simple filtering, `filter()` remains the preferred choice.

- **Lodash or Underscore**: Libraries like Lodash provide utility functions that can sometimes simplify and optimize operations on arrays. For simple tasks, they might add overhead, but their modularity can be beneficial for more complex operations.

- **For Loop**: A traditional `for` loop could be used for more control and potential optimization, although it typically sacrifices readability for performance.

In conclusion, the methods tested provide various options for filtering empty rows from a 2D array, highlighting the trade-offs between performance and readability. Software engineers can use this benchmark as a reference when deciding on the appropriate filtering mechanism for their projects.

Related benchmarks:

Filtering out empty rows from a 2D Array (version: 1)

Comparing performance of: Double negation (!!row.length) vs Comparison (row.length > 0) vs Double negation (!!row) vs Boolean constructor

Created: 10 days ago by: Registered User

Jump to the latest result

Double negation (!!row.length)

Comparison (row.length > 0)

Double negation (!!row)

Boolean constructor

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 10 days ago):