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详解angularjs利用ui-route异步加载组件

2019-11-19 16:32:13
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ui-route相比于angularjs的原生视图路由更好地支持了路由嵌套,状态转移等等。随着视图不断增加,打包的js体积也会越来越大,比如我在应用里面用到了wangeditor里面单独依赖的jquery就300多k。异步加载各个组件就很有必要。在这里我就以ui-route为框架来进行异步加载说明。

首先看一下路由加载文件

angular.module('webtrn-sns').config(['$stateProvider', function ($stateProvider) {  $stateProvider.state({      name: 'home.message',      url: '/message',      abstract: true,      templateProvider: ['resources', function (resources) {        return resources.template      }],      controllerProvider: ['resources', (resources)=> {        return resources.controller      }],      onEnter: ['resources', (resources)=>resources.css.use()],      onExit: ['resources', (resources)=>resources.css.unuse()],      resolve: {        resources: ()=> {          return new Promise(            resolve => {              require([], () => {                resolve({                  css: require('./css/message_box.css'),                  template: require('./html/message_box.html'),                  controller: require('./js/message_box.js')                })              })            }          );        }      }    }  ).state({      name: 'home.message.add_message',      url: '/add_message?isReply&toUid&title',      params: {isReply: null, toUid: null, title: null},      templateProvider: ['resources', function (resources) {        return resources.template      }],      controllerProvider: ['resources', (resources)=> {        return resources.controller      }],      onEnter: ['resources', (resources)=>resources.css.use()],      onExit: ['resources', (resources)=>resources.css.unuse()],      resolve: {        resources: ()=> {          return new Promise(            resolve => {              require(['./js/message.js'], () => {                resolve({                  css: require('./css/add_message.css'),                  template: require('./html/add_message.html'),                  controller: require('./js/add_message.js')                })              })            }          );        }      }    }  )}])

这个是路由状态的一个声明文件,name,url,param字段的方式不变,关键是看resolve这个部分。根据ui-route的resolve文档,resolve是为了给state或者controller进行自定义注入对象的。

下面是举出文档中关于resolve的例子:

$stateProvider.state('myState', {   resolve:{     // Example using function with simple return value.     // Since it's not a promise, it resolves immediately.     simpleObj: function(){      return {value: 'simple!'};     },     // Example using function with returned promise.     // This is the typical use case of resolve.     // You need to inject any services that you are     // using, e.g. $http in this example     promiseObj: function($http){      // $http returns a promise for the url data      return $http({method: 'GET', url: '/someUrl'});     },     // Another promise example. If you need to do some      // processing of the result, use .then, and your      // promise is chained in for free. This is another     // typical use case of resolve.     promiseObj2: function($http){      return $http({method: 'GET', url: '/someUrl'})        .then (function (data) {          return doSomeStuffFirst(data);        });     },         // Example using a service by name as string.     // This would look for a 'translations' service     // within the module and return it.     // Note: The service could return a promise and     // it would work just like the example above     translations: "translations",     // Example showing injection of service into     // resolve function. Service then returns a     // promise. Tip: Inject $stateParams to get     // access to url parameters.     translations2: function(translations, $stateParams){       // Assume that getLang is a service method       // that uses $http to fetch some translations.       // Also assume our url was "/:lang/home".       return translations.getLang($stateParams.lang);     },     // Example showing returning of custom made promise     greeting: function($q, $timeout){       var deferred = $q.defer();       $timeout(function() {         deferred.resolve('Hello!');       }, 1000);       return deferred.promise;     }   },   // The controller waits for every one of the above items to be   // completely resolved before instantiation. For example, the   // controller will not instantiate until promiseObj's promise has    // been resolved. Then those objects are injected into the controller   // and available for use.    controller: function($scope, simpleObj, promiseObj, promiseObj2, translations, translations2, greeting){     $scope.simple = simpleObj.value;     // You can be sure that promiseObj is ready to use!     $scope.items = promiseObj.data.items;     $scope.items = promiseObj2.items;     $scope.title = translations.getLang("english").title;     $scope.title = translations2.title;     $scope.greeting = greeting;   }  })

我们可以看到resolve的对象是支持Promise的。

再回到我们之前的代码templateProvider和controllerProvider我们注入了resources的模板对象和controller对象,onEnter和onExit注入了css模块。

如果controller中依赖了服务怎么办的?

resolve: {  resources: ()=> {    return new Promise(      resolve => {        require(['./js/message.js'], () => {          resolve({            css: require('./css/add_message.css'),            template: require('./html/add_message.html'),            controller: require('./js/add_message.js')          })        })      }    );  }}

可以在require里面将服务注入,如代码中的message.js。而为了将服务进行异步加载我们不能用普通的.factory或者.service。而需要调用$provide.factory或者$provide.service

如果采用webpack进行编译打包的话就需要webpack.optimize.CommonsChunkPlugin的支持,这样可以对js进行拆分打包,达到异步加载js的目的。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持武林网。

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