```ts
export function fieldOf(record: Record<string, number>, field: string): number {
  if (!record.hasOwnProperty(field)) {
    throw new Error(`Record does not have field ${field}`);
  }
  return record[field];
}

export function sortPairs(records: Record<string, number>[], field: string): Record<string, number>[] {
  const sortedRecords = records.slice().sort((a, b) => {
    if (a[field] === b[field]) {
      return -1; // Keep the earlier record earlier
    }
    return a[field] < b[field] ? -1 : 1;
  });
  return sortedRecords;
}
```