```ts
/** a divided by b. */
export function safeDivide(a: number, b: number): number {
  if (b === 0) { throw new Error('Attempted to divide by zero'); }
  if (!isFinite(Number(a)) || !isFinite(Number(b))) {
    throw new Error('Both arguments must be finite numbers');
  }
  return a / b;
}

const isFinite = Number.isFinite;
```