hexojs/hexo · critical · TypeError

Invalid config detected: "root" should be string, not ${type

Error message

Invalid config detected: "root" should be string, not ${typeof config.root}!

What it means

Thrown by validate_config (lib/hexo/validate_config.ts:23). config.root (the path under which the site is served) must be a string. It is checked after url, so url already passed.

Source

Thrown at lib/hexo/validate_config.ts:23

export = (ctx: Hexo): void => {
  const { config, log } = ctx;

  log.info('Validating config');

  // Validation for config.url && config.root
  if (typeof config.url !== 'string') {
    throw new TypeError(`Invalid config detected: "url" should be string, not ${typeof config.url}!`);
  }
  try {
    // eslint-disable-next-line no-new
    new URL(config.url);
    assert(new URL(config.url).protocol.startsWith('http'));
  } catch {
    throw new TypeError('Invalid config detected: "url" should be a valid URL!');
  }

  if (typeof config.root !== 'string') {
    throw new TypeError(`Invalid config detected: "root" should be string, not ${typeof config.root}!`);
  }
  if (config.root.trim().length <= 0) {
    throw new TypeError('Invalid config detected: "root" should not be empty!');
  }

  if (!config.timezone) {
    log.warn('No timezone setting detected! Using LocalTimeZone as the default timezone.');
    log.warn('This behavior will be changed to UTC in the next major version. Please set timezone explicitly (e.g. LocalTimeZone or America/New_York) in _config.yml to avoid this warning.');
  } else {
    const configTimezone = moment.tz.zone(config.timezone);
    if (!configTimezone) {
      log.warn(
        `Invalid timezone setting detected! "${config.timezone}" is not a valid timezone.`
      );
    } else {
      const machineTimezone = moment.tz.guess();
      if (configTimezone.name !== machineTimezone) {
        log.warn(

View on GitHub (pinned to 059cb17494)

Solutions

1. Set root to a string path in _config.yml, typically root: /.
2. If root is computed by a plugin, ensure it returns a string.
3. Search for assignments to config.root and fix non-string producers.

Example fix

# before
root: 0

# after
root: /

if (typeof hexo.config.root !== 'string') {
  throw new Error(`_config.yml 'root' must be a string, got ${typeof hexo.config.root}`);
}

When it happens

Trigger: config.root is a number, object, array, or null/undefined in _config.yml (e.g. root: 0, root: [/], root omitted and defaulted to a non-string).

Common situations: YAML parsing a bare token into a non-string; a theme/plugin overriding root with a non-string; deleting the root line expecting a default but a plugin set it to undefined; config merge producing a non-string.

Related errors

• Invalid config detected: "root" should not be empty!
• Invalid config detected: "url" should be string, not ${typeo
• Invalid config detected: "url" should be a valid URL!
• fn must be a function
• name is required

AI-assisted analysis of hexojs/hexo@059cb17494 (2026-08-12). Data as JSON: /api/errors/98316aedaa18b6cc. Report an issue: GitHub.