require.ensure([], (require)这段代码怎么理解？

Question

export default (store)=> ({
    path: '/',
    //component: require('./containers/App.react').default,
    getComponent(nextState, cb) {

        require.ensure([], (require) => {
            // 根据路由手动注入当前操作reducer
            const reducer = require('./reducers/app.reducer.js').default;
            injectReducer(store, {key: 'app', reducer: reducer});

            cb(null, require('./containers/App.react').default);
        }, 'app');
    },
    onEnter: function (nextState, replace) {
        if(!checkLogin()){
            //replace('/login');
            //window.location.href = ENV.SSOLogin;
            //不同认证方式的处理
            if(ENV.AuthType == 1){
                window.location.href = ENV.SSOLogin;
                return false;
            }else{
                window.location.hash = ENV.baseLogin;
            }
            return false;
        }

    },
    /*indexRoute: {
     //component: require('./containers/Dashboard.react').default
     //getComponent(nextState, cb) {
     // require.ensure([], (require) => {
     // cb(null, require('./routes/operation/containers/Operation.react').default)
     // }, 'operation');
     // }
     },*/
    childRoutes: [
        require('./routes/operation').default(store),
        require('./routes/report').default(store),
    ],
    indexRoute:{
        component: require('./routes/operation').default(store),
    }
});

Answer 1

require.ensure是webpack提供的语法，按需加载