```ts
/**
 * Safely divides two numbers, throwing an Error for invalid input.
 */
export function safeDivide(a: number, b: number): number {
  // Ensure both arguments are finite numbers
  if (!Number.isFinite(a) || !Number.isFinite(b)) {
    throw new Error('Arguments must be finite numbers');
  }
  // Reject zero divisor (covers +0 and -0)
  if (b === 0) {
    throw new Error('Divisor cannot be zero');
  }
  return a / b;
}
```