videojs/video.js · error · Error

Illegal plugin name, "${name}", must be a string, was ${type

Error message

Illegal plugin name, "${name}", must be a string, was ${typeof name}.

What it means

registerPlugin requires the name to be a string because it is used as a Player.prototype method name and as a registry key. Non-string names (number, undefined, object) would silently create invalid method keys or be coerced unpredictably, so registration fails fast with the actual typeof for diagnostics.

Source

Thrown at src/js/plugin.js:348

  /**
   * Register a Video.js plugin.
   *
   * @param   {string} name
   *          The name of the plugin to be registered. Must be a string and
   *          must not match an existing plugin or a method on the `Player`
   *          prototype.
   *
   * @param   {typeof Plugin|Function} plugin
   *          A sub-class of `Plugin` or a function for basic plugins.
   *
   * @return {typeof Plugin|Function}
   *          For advanced plugins, a factory function for that plugin. For
   *          basic plugins, a wrapper function that initializes the plugin.
   */
  static registerPlugin(name, plugin) {
    if (typeof name !== 'string') {
      throw new Error(`Illegal plugin name, "${name}", must be a string, was ${typeof name}.`);
    }

    if (pluginExists(name)) {
      log.warn(`A plugin named "${name}" already exists. You may want to avoid re-registering plugins!`);
    } else if (Player.prototype.hasOwnProperty(name)) {
      throw new Error(`Illegal plugin name, "${name}", cannot share a name with an existing player method!`);
    }

    if (typeof plugin !== 'function') {
      throw new Error(`Illegal plugin for "${name}", must be a function, was ${typeof plugin}.`);
    }

    pluginStorage[name] = plugin;

    // Add a player prototype method for all sub-classed plugins (but not for
    // the base Plugin class).
    if (name !== BASE_PLUGIN_NAME) {
      if (Plugin.isBasic(plugin)) {

View on GitHub (pinned to c3a7e0e6d2)

Solutions

1. Pass a string literal name: videojs.registerPlugin('myPlugin', fn).
2. Coerce and validate before registering: if (typeof name !== 'string') throw new TypeError('name must be string').
3. Check that the variable holding the name was actually assigned.

Example fix

// before
videojs.registerPlugin(pluginConfig.key, fn); // key is undefined
// after
videojs.registerPlugin(String(pluginConfig.key), fn);

function safeRegisterPlugin(name, plugin) {
  if (typeof name !== 'string') {
    throw new TypeError(`plugin name must be string, got ${typeof name}`);
  }
  return videojs.registerPlugin(name, plugin);
}

const isPluginName = (n) => typeof n === 'string' && n.length > 0;

When it happens

Trigger: Calling videojs.registerPlugin(undefined, fn), registerPlugin(123, fn), registerPlugin({name:'x'}, fn), or registerPlugin(null, fn).

Common situations: Name sourced from a config key that is missing; programmatic registration with a non-string symbol; bundler transforming a name incorrectly.

Related errors

• Illegal plugin for "${name}", must be a function, was ${type
• Illegal component name, "${name}"; must be a non-empty strin
• Illegal component, "${name}"; ${reason}.
• Illegal plugin name, "${name}", cannot share a name with an
• Cannot de-register base plugin.

AI-assisted analysis of videojs/video.js@c3a7e0e6d2 (2026-08-13). Data as JSON: /api/errors/e243675341386e03. Report an issue: GitHub.