paperclipai/paperclip · error · Error

Cron expression must not be empty

Error message

Cron expression must not be empty

What it means

parseCron rejects the input because after trimming it is an empty string; a cron expression must contain five whitespace-separated fields, so there is nothing to parse.

Source

Thrown at server/src/services/cron.ts:207

/**
 * Parse a cron expression string into a structured {@link ParsedCron}.
 *
 * @param expression — A standard 5-field cron expression.
 * @returns Parsed cron with sorted valid values for each field.
 * @throws {Error} on invalid syntax.
 *
 * @example
 * ```ts
 * const parsed = parseCron("0 * * * *"); // every hour at minute 0
 * // parsed.minutes === [0]
 * // parsed.hours === [0,1,2,...,23]
 * ```
 */
export function parseCron(expression: string): ParsedCron {
  const trimmed = expression.trim();
  if (!trimmed) {
    throw new Error("Cron expression must not be empty");
  }

  const tokens = trimmed.split(/\s+/);
  if (tokens.length !== 5) {
    throw new Error(
      `Cron expression must have exactly 5 fields, got ${tokens.length}: "${trimmed}"`,
    );
  }

  return {
    minutes: parseField(tokens[0]!, FIELD_SPECS[0]!),
    hours: parseField(tokens[1]!, FIELD_SPECS[1]!),
    daysOfMonth: parseField(tokens[2]!, FIELD_SPECS[2]!),
    months: parseField(tokens[3]!, FIELD_SPECS[3]!),
    daysOfWeek: parseField(tokens[4]!, FIELD_SPECS[4]!),
  };
}

View on GitHub (pinned to 120ae5428f)

Solutions

1. Provide a non-empty cron expression.

When it happens

Trigger: Thrown at server/src/services/cron.ts:207 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of paperclipai/paperclip@120ae5428f (2026-08-18). Data as JSON: /api/errors/945b4e9dd63f65ad. Report an issue: GitHub.