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
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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。
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