koala73/worldmonitor · error · RangeError

maxCommands must be a positive integer

Error message

maxCommands must be a positive integer

What it means

chunkRedisCommands splits an array of Redis pipeline commands into chunks of at most maxCommands (default MAX_REDIS_PIPELINE_COMMANDS = 1000). It throws a RangeError when maxCommands is not an integer or is less than 1, because a non-positive chunk size would produce an infinite/invalid loop or empty chunks. This is an argument-validation guard on a helper used when writing feed-digest data to Redis.

Solutions

1. Pass a positive integer explicitly, or omit the argument to use MAX_REDIS_PIPELINE_COMMANDS (1000)
2. Fix the config/env source: coerce and validate with Number.isInteger before calling, and provide a sane fallback
3. If the value is computed, clamp it: maxCommands = Math.max(1, Math.floor(raw))
4. Add a unit test covering 0, negative, and NaN inputs to lock the validation behavior

Example fix

// before
chunkRedisCommands(cmds, Number(env.PIPELINE_BATCH)) // NaN
// after
const batch = Number(env.PIPELINE_BATCH);
chunkRedisCommands(cmds, Number.isInteger(batch) && batch > 0 ? batch : MAX_REDIS_PIPELINE_COMMANDS)

function assertPositiveInt(n) {
  if (!Number.isInteger(n) || n < 1) throw new RangeError(`maxCommands must be a positive integer, got ${n}`);
  return n;
}
chunkRedisCommands(cmds, assertPositiveInt(cfg.maxCommands));

function isPositiveInt(v: unknown): v is number {
  return typeof v === 'number' && Number.isInteger(v) && v >= 1;
}

try {
  chunks = chunkRedisCommands(cmds, maxCommands);
} catch (e) {
  if (e instanceof RangeError) chunks = chunkRedisCommands(cmds); // fall back to default 1000
  else throw e;
}

When it happens

Trigger: Calling chunkRedisCommands with an explicit maxCommands argument that is 0, negative, non-integer (e.g. NaN, 0.5), or a value derived from config/env math that evaluates to NaN.

Common situations: Env/config variable missing so Number(...) yields NaN; a computed limit like Math.floor(total/buckets) reaching 0; refactoring changed the default constant to a misparsed value; a caller passing user-supplied batch size unvalidated.

Related errors

• Invalid GEOSEARCH result
• Physical divergence snapshot must contain gold and silver…
• Redis transaction failed
• a pull_request payload is required
• A valid country code is required for a resilience score…

AI-assisted analysis of koala73/worldmonitor@e586b8b4b8 (2026-09-01). Data as JSON: /api/errors/cea3dd6678638f0e. Report an issue: GitHub.

Appendix: source

Thrown at server/worldmonitor/news/v1/list-feed-digest.ts:1658

    'HMGET', STORY_TRACK_KEY(h), ...fields,
  ]);
  const timeoutMs = redisTimeoutForDeadline(deadlineAt);
  if (timeoutMs === undefined) return new Map();
  const results = await runRedisPipeline(commands, false, timeoutMs);
  const map = new Map<string, StoryTrack>();
  for (let i = 0; i < titleHashes.length; i++) {
    const vals = results[i]?.result as string[] | null;
    if (!vals || !vals[0]) continue; // firstSeen missing → new story
    map.set(titleHashes[i]!, {
      firstSeen:    Number(vals[0]),
      lastSeen:     Number(vals[1] ?? 0),
      mentionCount: Number(vals[2] ?? 0),
      sourceCount:  Number(vals[3] ?? 0),
    });
  }
  return map;
}

function parseRedisTimestamp(value: unknown): number | undefined {
  if (value === null || value === undefined) return undefined;
  if (typeof value !== 'string' && typeof value !== 'number') return undefined;
  if (typeof value === 'string' && value.trim().length === 0) return undefined;
  const parsed = Number(value);
  return Number.isFinite(parsed) ? parsed : undefined;
}

function chunkRedisCommands(
  commands: Array<Array<string | number>>,
  maxCommands: number = MAX_REDIS_PIPELINE_COMMANDS,
): Array<Array<Array<string | number>>> {
  if (!Number.isInteger(maxCommands) || maxCommands < 1) {
    throw new RangeError('maxCommands must be a positive integer');
  }
  const chunks: Array<Array<Array<string | number>>> = [];
  for (let offset = 0; offset < commands.length; offset += maxCommands) {
    chunks.push(commands.slice(offset, offset + maxCommands));

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