AngularJS Promise

先看两个官方文档
https://docs.angularjs.org/api/ng/service/$http http://fdietz.github.io/recipes-with-angular-js/consuming-external-services/deferred-and-promise.html
首先呢 要知道$http和$.ajax一样 本身是可以直接链式的调用 .success .error 的(jQuery里面的ajax是failed)

那么为什么我还需要dfd呢 dfd更灵活，可以在很多地方使用 不仅仅局限于http请求

这里有个比较搓的例子 感受一下他们的区别

var list = dataSource.makeHttpRequest('/list', 'POST', {
"xxx": xxx
});
list.httpRequest.success(function(data){
console.log(data);
});
list.promise.then(function(data){
console.log(data);
});

dataSource是我定义的一个factory 返回的httpRequest就是$http.post 而Promise则是dfd.promise

myApp.factory('dataSource', ['$http', '$q', function($http, $q) {
return {
makeHttpRequest: function(url, method, params) {
var httpRequest;
var defer = $q.defer();

if (method == 'GET') {

//$http.get()
} else if (method == 'POST') {
httpRequest = $http.post(url, params);
httpRequest.success(function(data) {
if (data.status == 0) {
defer.resolve(data);
} else {
defer.reject(data);
}

}).error(function(msg) {
defer.reject(msg);
});
}

return {
promise: defer.promise,
httpRequest: httpRequest
}
}
}
}]);