```ts
export function rangeCheck(readings: number[], low: number, high: number): boolean {
  if (readings.length === 0) return true;

  for (const reading of readings) {
    if (reading < low || reading > high) {
      throw new Error(`Reading ${reading} is outside the valid range [${low}, ${high}]`);
    }
  }

  return true;
}
```