```ts
/** a divided by b. */
export function safeDivide(a: number, b: number): number {
  if (typeof a !== 'number' || typeof b !== 'number') {
    throw new Error("Both arguments must be finite numbers.");
  }
  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 (including negative zero).");
  }

  return a / b;
}
```