```ts
export function paceOf(seconds: number, kilometres: number): number {
  if (kilometres === 0) {
    throw new Error("Distance cannot be zero.");
  }
  return Math.floor(seconds / kilometres);
}

export function paceList(legs: { seconds: number; kilometres: number }[]): number[] {
  if (! legs || ! legs.length) {
    throw new Error("Legs must not be empty.");
  }

  const pace = [];
  for (const leg of legs) {
    if (leg.kilometres === 0) {
      throw new Error("Distance cannot be zero.");
    }
    pace.push(Math.floor(leg.seconds / leg.kilometres));
  }
  return pace;
}
```