如何解决$ q.all？

Question

我有两个功能,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;
    }

现在我有一个主题列表,一旦这两个承诺得到解决,我想立即更新

    var topics = {      
        firstTopic: 'myApp.firstTopic.',  
        secondTopic: 'myApp.secondTopic.',
        thirdTopic: 'myApp.thirdTopic.',
        fourthTopic: 'myApp.fourthTopic.',
    };

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?

    });
}

Answer 1

$q.all当任何承诺被拒绝时,当您传递的所有承诺被解决或拒绝时,会创建一个自动解决的承诺.

如果你像它一样传递一个数组,那么处理成功解析的函数将接收一个数组,每个项目是相同索引的promise的解析,例如:

  var resolveTopics = function() {
    $q.all([getToken(), getUserId()])
    .then(function(resolutions){
      var token  = resolutions[0];
      var userId = resolutions[1];
    });
  }

我个人认为传递all一个对象更具可读性,这样你就可以在你的处理程序中获得一个对象,其中值是相应promise的解析,例如:

  var resolveTopics = function() {
    $q.all({token: getToken(), userId: getUserId()})
    .then(function(resolutions){
      var token  = resolutions.token;
      var userId = resolutions.userId;
    });
  }