Valid JS treated as invalid by editor

var fn = function () {
    var actions = new DSsysLibActionIndex.lib.ActionIndex();
    actions.registerAction('asyncModalUpdateModelList', function (modal, params) {
        import('./actions/asyncModalUpdateModelList.js').then(function (Module) {
            var action = new Module.AsyncModalUpdateModelListAction(modal, params);
            action.run();
        });
    });
    actions.registerAction('asyncModalUpdateAuthorityList', function (modal, params) {
        import('./actions/asyncModalUpdateAuthorityList.js').then(function (Module) {
            var action = new Module.AsyncModalUpdateAuthorityListAction(modal, params);
            action.run();
        });
    });
};