Javascript Angular 解析同步查询(按顺序)

Question

我正在尝试在 javascript 中使用 Parse 按顺序同步进行两个查询:

var innerQuery = new Parse.Query(Attendees);
    innerQuery.equalTo("user_id",$localStorage.username);
    innerQuery.equalTo("status","confirmed")
    innerQuery.equalTo("code_verified",false)

    var innerQuerytrue = new Parse.Query(Attendees);
    innerQuerytrue.equalTo("user_id",$localStorage.username);
    innerQuerytrue.equalTo("status","confirmed")
    innerQuerytrue.equalTo("code_verified",true)


    innerQuery.find({}) 
    innerQuerytrue.find({}) 


    var eventDetails = []

    var queryfalse = new Parse.Query(Events)
    queryfalse.matchesKeyInQuery("id_event","event_id",innerQuery);

    var querytrue = new Parse.Query(Events)
    querytrue.matchesKeyInQuery("id_event","event_id",innerQuerytrue);


    queryfalse.find().then(function(results){
        for (var i in results) {
              var object = results[i];
              var eventId = object.get("id_event");
              var eventname = object.get("event_name");
              var datestart = object.get("date_start");
              var location = object.get("location");
              var eventimagefile = object.get("event_image");
              var eventimageurl = eventimagefile.url();
              eventDetails.push({'name':eventname,'eventId':eventId, 'location':location, 'datestart':datestart, 'eventphoto':eventimageurl,'verified':false})      
        }

    }).then(function(){
        querytrue.find().then(function(results1){
            for (var i in results1) {
                  var object = results1[i];
                  var eventId = object.get("id_event");
                  var eventname = object.get("event_name");
                  var datestart = object.get("date_start");
                  var location = object.get("location");
                  var eventimagefile = object.get("event_image");
                  var eventimageurl = eventimagefile.url();
                  eventDetails.push({'name':eventname,'eventId':eventId, 'location':location, 'datestart':datestart, 'eventphoto':eventimageurl,'verified':true})      
            }
        })

    }).then(function(){
        $scope.events = eventDetails;
    })

第二个查询 queryfalse 并不总是执行。我正在使用 promises，但不确定它是否是正确的使用方式。

Answer 1

只需添加 return 以将 querytrue.find().then() 返回的 promise 传递到链下，以便下一个 then() 在 promise 得到解决之前不会执行。这也使您的代码更扁平，以避免深度嵌套的 promise 。

    queryfalse.find().then(function(results){
        // code clipped for brevity
    }).then(function(){
        return querytrue.find().then(function(results1){
            // code clipped for brevity
        });
    }).then(function(){
        $scope.events = eventDetails;
    });

这是一个可以证明这一点的工作 plunker:https://plnkr.co/edit/SwPIC1K6yEhEgpIlxoEo?p=preview