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') }) }) } ); } }