```ts
/**
 * a divided by b. Throws Error if b is zero or non-finite, including -0.
 * @param a - The numerator.
 * @param b - The denominator.
 * @returns The result of a / b.
 */
export function safeDivide(a: number, b: number): number {
  if (!Number.isFinite(a) || !Number.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;
}
```