code: function isInternalComponentType(type) {
    return (
      typeof type === 'function' &&
      typeof type.prototype !== 'undefined' &&
      typeof type.prototype.mountComponent === 'function' &&
      typeof type.prototype.receiveComponent === 'function'
    );
  }
docs: Check if the type reference is a known internal type. I.e. not a user
  provided composite type.
  
  @param {function} type
  @return {boolean} Returns true if this is a valid internal type.