```ts
/** Safely divides a by b. */
export function safeDivide(a: number, b: number): number {
  if (!isFinite(a) || !isFinite(b)) {
    throw new Error('Both arguments must be finite numbers');
  }
  if (b === 0 || b === -0) {
    throw new Error('Divisor cannot be zero');
  }
  return a / b;
}

// Helper function to check if the number is finite
function isFinite(n: number): boolean {
  return Number.isFinite(n);
}
```