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// String Literal Types Example
// This demonstrates how string literal types work in TypeScript

// Define a variable that can only accept specific string values
// In TypeScript:
// let direction: "north" | "south" | "east" | "west";

// Function that validates if a direction is acceptable
function isValidDirection(dir) {
  // In TypeScript, this check would happen at compile time
  const validDirections = ["north", "south", "east", "west"];
  return validDirections.includes(dir);
}

// Function that uses direction (simulating TypeScript's type checking)
function move(direction) {
  if (!isValidDirection(direction)) {
    throw new Error(`Invalid direction: ${direction}. Must be north, south, east, or west.`);
  }
  
  console.log(`Moving ${direction}`);
}

// Valid direction examples
console.log("Valid directions examples:");
try {
  move("north");
  move("east");
  move("south");
  move("west");
} catch (error) {
  console.log(error.message);
}

// Invalid direction examples
console.log("\nInvalid directions examples:");
try {
  move("northeast");
  console.log("This would not execute in TypeScript due to compiler error");
} catch (error) {
  console.log(error.message);
}

try {
  move("up");
  console.log("This would not execute in TypeScript due to compiler error");
} catch (error) {
  console.log(error.message);
}

// In TypeScript, invalid assignments would cause compiler errors:
console.log("\nIn TypeScript, these would be compile-time errors:");
console.log('direction = "northeast"; // Error: Type \'"northeast"\' is not assignable to type...');
console.log('move("up");        // Error: Argument of type \'"up"\' is not assignable to...');

Valid directions examples:
Moving north
Moving east
Moving south
Moving west

Invalid directions examples:
Invalid direction: northeast. Must be north, south, east, or west.
Invalid direction: up. Must be north, south, east, or west.

In TypeScript, these would be compile-time errors:
direction = "northeast"; // Error: Type '"northeast"' is not assignable to type...
move("up");        // Error: Argument of type '"up"' is not assignable to...