Refactor Key Handling in Snake Game to Use Lookup Table for Arrow Keys

I suggest refactoring the handleArrowKeys method to replace the current switch statement with a more maintainable and concise lookup table for handling key presses. This approach follows modern JavaScript best practices and improves code readability.

Proposed Changes:

• Replace the switch statement with a keyToDirection object that maps key codes to movement directions.
• Use the ?? (nullish coalescing) operator to handle invalid key presses more cleanly.
• Ensure const and let are used for block-scoped variables to improve scoping and maintainability.

Benefits:

• Simplifies the key handling logic, making it easier to read and maintain.
• Enhances flexibility for future key mappings or modifications.
• Adheres to modern JavaScript standards, leading to better performance and clarity.

Here is an example of the proposed refactor:

const keyToDirection = {
    37: 3, // Left arrow
    65: 3, // 'A' key
    38: 0, // Up arrow
    87: 0, // 'W' key
    39: 1, // Right arrow
    68: 1, // 'D' key
    40: 2, // Down arrow
    83: 2  // 'S' key
};

const directionFound = keyToDirection[keyNum] ?? -1;