[英]Resolving a promise in a 'then' statement
With AngularJS, I resolve my promises directly in the service just like this: 使用AngularJS,我可以像这样直接在服务中兑现我的承诺:
.factory('movieService', function($http, $log, $q) {
return {
getMovie: function(movie) {
var deferred = $q.defer();
$http.get('/api/v1/movies/' + movie)
.success(function(data) {
deferred.resolve({
title: data.title,
cost: data.price});
}).error(function(msg, code) {
deferred.reject(msg);
$log.error(msg, code);
});
return deferred.promise;
}
}
});
As stated in the documentation ( https://docs.angularjs.org/api/ng/service/ $http#) : 如文档中所述( https://docs.angularjs.org/api/ng/service/ $ http#):
The $http legacy promise methods success and error have been deprecated.
$ http旧式的Promise方法成功和错误已被弃用。 Use the standard then method instead.
请改用标准然后方法。 If $httpProvider.useLegacyPromiseExtensions is set to false then these methods will throw $http/legacy error.
如果$ httpProvider.useLegacyPromiseExtensions设置为false,则这些方法将引发$ http / legacy错误。
So success
and error
got deprecated. 因此,不赞成
success
和error
。
How can I resolve a promise in a then
statement ? 我如何在
then
语句中兑现承诺?
Regards. 问候。
Your code can be rewritten as: 您的代码可以重写为:
.factory('movieService', function($http, $log, $q) {
return {
getMovie: function(movie) {
var deferred = $q.defer();
$http.get('/api/v1/movies/' + movie).then(function(response){
var data = response.data;
deferred.resolve({
title: data.title,
cost: data.price
});
}, function(msg, code) {
deferred.reject(msg);
$log.error(msg, code);
});
return deferred.promise;
}
};
});
Although you're doing a bit more work than necessary. 尽管您要做的工作比必要的多。 It can be shortened down to:
它可以缩短为:
.factory('movieService', function($http, $log, $q) {
return {
getMovie: function(movie) {
return $http.get('/api/v1/movies/' + movie).then(function(response){
var data = response.data;
return {
title: data.title,
cost: data.price
};
}, function(msg, code) {
$log.error(msg, code);
});
}
};
});
Just pass two functions to then()
as parameters, the first being for success, and the second being for failure. 只需将两个函数作为参数传递给
then()
,第一个用于成功,第二个用于失败。
...
$http.get('/api/v1/movies/' + movie)
.then(function(result) {
//Your success code here
},
function(result) {
//Your fail code here
});
...
Strictly speaking, though, then()
returns a promise. 但是严格来说,
then()
返回一个promise。 What you're doing is waiting for it to resolve, then using that resolve to resolve another promise with the same data. 您正在做的是等待其解决,然后使用该解决方案来解决另一个具有相同数据的承诺。 You don't need to bother;
您无需打扰; just return the
$http
chain. 只需返回
$http
链。 Admittedly, they could be a little clearer about then()
in the documentation for $http and $q . 诚然,在$ http和$ q的文档中,它们可能对
then()
更为清晰。
.factory('movieService', function ($http, $log, $q) { return { getMovie: function (movie) { var deferred = $q.defer(); $http.get('/api/v1/movies/' + movie).then( //Success as first parameter function (data) { deferred.resolve({ title: data.title, cost: data.price }); }, // Error as second parameter function (msg, code) { deferred.reject(msg); $log.error(msg, code); } ); return deferred.promise; } } });
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