Big O for VSCode

Big O for VSCode is a Visual Studio Code extension that analyzes JavaScript and TypeScript files and adds an estimated Big O time complexity comment above each function. This helps developers quickly assess the computational cost of their functions during development.

✨ Features

• Detects and analyzes function definitions (function, arrow functions).
• Estimates time complexity using a basic heuristic:
  • O(1) – No loops detected
  • O(n) – One loop or loop-like expression
  • O(n^2) – Nested or multiple loops detected
  • O(2^n) – Recursive functions detected
• Inserts a vs code lens like // Complexity: O(n) above the function.

⚠️ Note: This extension uses a simple static analysis technique and does not perform full control-flow or data-flow analysis. Use results as rough estimates only.

🎥 Demo

Before:

function sum(arr) {
  let total = 0;
  for (let i = 0; i < arr.length; i++) {
    total += arr[i];
  }
  return total;
}

After running Analyze Function Complexity:

// Complexity: O(n)
function sum(arr) {
  let total = 0;
  for (let i = 0; i < arr.length; i++) {
    total += arr[i];
  }
  return total;
}

📎 Sample

🚀 Usage

• Open a JavaScript or TypeScript file.
• Open the Command Palette (Ctrl+Shift+P or Cmd+Shift+P on macOS).
• Run Analyze Function Complexity.

The extension will analyze the open file and insert a complexity comment above each function.

🔮 Next Steps

Planned enhancements for future versions include:

• Multi-language support:

  • ✅ JavaScript / TypeScript (current)

  • 🟡 Python: Detect def functions and analyze for, while, map, list comprehensions, etc.

  • 🟡 Go: Parse func declarations and loops (for, range).

• Improved complexity estimation with:

  • Support for recursive functions.

  • Include other bigO common notations:

    • ✅ O(1) (Constant time)
    • 🟡 O(log n) (Logarithmic time)
    • ✅ O(n) (Linear time)
    • 🟡 O(n log n)
    • ✅ O(n^2) (Quadratic time)
    • ✅ O(2^n) (Exponential time)

  • Configurable detection rules via settings.

🔗 Useful links

• How to create a vscode extension
• how to publish a vscode extension

📄 License

This project is open-source and available under the MIT License.