code: function _initModules() {
    const modules = store.modules;
  
    Object.keys(modules).forEach(function(key) {
      if (typeof modules[key].onRegisterCallback === 'function') {
        modules[key].onRegisterCallback();
      }
    });
  }
docs: /*
  TODO: This could cause issues if the module was already initialized for
  the store. As there's nothing stopping implementers from calling `init`
  multiple times. Modules should self-check if they have already been
  registered to prevent issues.
   
  Iterate over our store's modules. If the module has an `onRegisterCallback`
  call it. This hook can be used to setup any global store requirements per
  module.
  @private
  @method
  @returns {void}