kafka-pub-sub/validation/validateTopic.js

Enterprise-grade Kafka publish/subscribe library for Node.js — producer pool, batch sending, DLQ, SSL/SASL, multi-broker, and real-world industry examples.

const Joi = require('joi');

// Kafka's official topic naming rule: alphanumeric, dot, dash, underscore; max 249 chars
const TOPIC_REGEX = /^[a-zA-Z0-9._-]+$/;

/**
 * Validates a Kafka topic name against Kafka's official naming rules.
 *
 * Rules:
 *  - Must be a non-empty string
 *  - 1–249 characters (Kafka broker hard limit)
 *  - Only alphanumeric characters, dots (.), hyphens (-), and underscores (_)
 *
 * @param {string} topic - The topic name to validate.
 * @throws {Error} When the topic is invalid.
 */
const validateTopic = (topic) => {
  const schema = Joi.object()
    .keys({
      topic: Joi.string().min(1).max(249).pattern(TOPIC_REGEX).required().description('Kafka topic name'),
    })
    .unknown();

  const { error } = schema.prefs({ errors: { label: 'key' } }).validate({ topic });

  if (error) {
    throw new Error(
      'Invalid topic: must be a non-empty string up to 249 characters containing only alphanumeric characters, dots (.), hyphens (-), or underscores (_)',
    );
  }
};

module.exports = validateTopic;