javascript 如何解决$q.all？
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How to resolve $q.all?
提问by gumenimeda
I have 2 functions, both returning promises:
我有两个函数，都返回承诺：
var getToken = function() {
var tokenDeferred = $q.defer();
socket.on('token', function(token) {
tokenDeferred.resolve(token);
});
//return promise
return tokenDeferred.promise;
}
var getUserId = function() {
var userIdDeferred = $q.defer();
userIdDeferred.resolve('someid');
return userIdDeferred.promise;
}
Now I have a list of topics that I would like to update as soon as these two promises get resolved
现在我有一个主题列表，我想在这两个承诺得到解决后立即更新
var topics = {
firstTopic: 'myApp.firstTopic.',
secondTopic: 'myApp.secondTopic.',
thirdTopic: 'myApp.thirdTopic.',
fourthTopic: 'myApp.fourthTopic.',
};
Resolved topics should look like this myApp.firstTopic.someid.sometoken
已解决的主题应如下所示 myApp.firstTopic.someid.sometoken
var resolveTopics = function() {
$q.all([getToken(), getUserId()])
.then(function(){
//How can I resolve these topics in here?
});
}
回答by mfollett
$q.allcreates a promise that is automatically resolved when all of the promises you pass it are resolved or rejected when anyof the promises are rejected.
$q.all创建一个承诺，当您传递的所有承诺都被解决或拒绝任何承诺时，该承诺将自动解决。
If you pass it an array like you do then the function to handle a successful resolution will receive an array with each item being the resolution for the promise of the same index, e.g.:
如果你像你一样传递一个数组，那么处理成功解析的函数将接收一个数组，其中每个项目都是相同索引的承诺的解析，例如：
var resolveTopics = function() {
$q.all([getToken(), getUserId()])
.then(function(resolutions){
var token = resolutions[0];
var userId = resolutions[1];
});
}
I personally think it is more readable to pass allan object so that you get an object in your handler where the values are the resolutions for the corresponding promise, e.g.:
我个人认为传递all对象更具可读性，以便您在处理程序中获得一个对象，其中值是相应承诺的分辨率，例如：
var resolveTopics = function() {
$q.all({token: getToken(), userId: getUserId()})
.then(function(resolutions){
var token = resolutions.token;
var userId = resolutions.userId;
});
}
