```ts
/** Divides a by b safely, throwing on invalid input or division by zero. */
export function safeDivide(a: number, b: number): number {
  if (!Number.isFinite(a) || !Number.isFinite(b)) {
    throw new Error('Arguments must be finite numbers');
  }
  if (b === 0) {
    throw new Error('Division by zero');
  }
  return a / b;
}
```
