```ts
export function caseCount(text: string): number[] {
  if (!text) return [0, 0];
  
  let caps = 0;
  let lows = 0;
  
  for (const char of text) {
    if (char >= 'A' && char <= 'Z') {
      caps++;
    } else if (char >= 'a' && char <= 'z') {
      lows++;
    }
  }
  
  return [caps, lows];
}
```