```ts
/** A code padded with zeros to a fixed width. */
export function padCode(code: string, width: number): string {
  if (typeof code !== 'string' || typeof width !== 'number') {
    throw new Error("Both code and width must be strings or numbers.");
  }

  const minLength = Math.min(width, code.length);
  return code.slice(0, minLength) + "0".repeat(width - minLength);
}
```