Function isValidCron

src/lib/cron-parser.ts:230–271

(expr: string)

 * Validate a cron expression
 */
export function isValidCron(expr: string): boolean {
  const parts = parseCron(expr);
  if (!parts) return false;

  const validateField = (field: string, min: number, max: number): boolean => {
    if (field === '*') return true;
    
    // Handle step values (*/n or n/m)
    if (field.includes('/')) {
      const [range, step] = field.split('/');
      if (range !== '*' && !validateField(range, min, max)) return false;
      const stepNum = parseInt(step);
      return !isNaN(stepNum) && stepNum > 0;
    }

    // Handle ranges (n-m)
    if (field.includes('-')) {
      const [start, end] = field.split('-').map(Number);
      return !isNaN(start) && !isNaN(end) && start >= min && end <= max && start <= end;
    }

    // Handle lists (n,m,...)
    if (field.includes(',')) {
      return field.split(',').every(v => {
        const num = parseInt(v);
        return !isNaN(num) && num >= min && num <= max;
      });
    }

    // Single value
    const num = parseInt(field);
    return !isNaN(num) && num >= min && num <= max;
  };

  return (
    validateField(parts.minute, 0, 59) &&
    validateField(parts.hour, 0, 23) &&
    validateField(parts.dayOfMonth, 1, 31) &&
    validateField(parts.month, 1, 12) &&
    validateField(parts.dayOfWeek, 0, 6)
  );
}

/**
 * Common cron presets