javascript - Angularjs 指令属性属性全部未定义

Question

我创建了一个具有以下定义的指令

LastMeet.directive("progressBar", function() {
  return {
    restrict: "A",
    scope: {
      meeting: "&meeting"
    },
    link: function(scope, elm, attrs) {

      var meeting = scope.meeting();

      // Gather the details we need about this meeting
      var startDate = scope.meeting().start_datetime;
      var deadline  = scope.meeting().deadline;
      var complete  = scope.meeting().percentage_complete;
      console.log(meeting);
      console.log(meeting["start_datetime"]);

      // No point doing anything if we're already at 100%      
      if (complete < 100.0) {
        // Calculate how much to increment by every second
        var diff      = deadline - startDate;
        var increment = diff / 60.0;

        var timer;

        scope.percentage = complete;

        scope.onTimeout = function() {

          if (scope.percentage < 100.0) { 
            scope.percentage += increment;
            elm.css({ right: 100 - percentage + "%" });
            timer = $timeout(scope.onTimeout, 1000);
          }

        }

        // Setup our timer and get going :)
        timer = $timeout(scope.onTimeout, 1000);
      }

    }
  }
})

session 属性是一个具有许多不同属性的对象。如您所见，我添加了 2 个控制台输出，一个用于 session 本身，另一个用于我尝试访问的属性之一。我的控制台有以下输出

b {$resolved: false, $then: function, $get: function, $save: function, $query: function…}
   $resolved: true
   $then: function (callback, errback) {
   agenda_items: Array[2]
   deadline: 1365897600
   description: "Meeting to discuss the progress of LastMeet"
   faye_token: "7468585e529849ca992efbd3b9de6337"
   icon: null
   id: 20
   name: "LastMeet"
   percentage_complete: 100
   start_datetime: 1365897600
   __proto__: b

这是 session 对象的输出，它清楚地显示了包含的 start_datetime 属性。然而，第二个控制台输出很简单

undefined

为什么 session 对象在那里，而且我可以看到所有内容，但当我尝试访问包含的属性时，我每次都只是未定义？

Answer 1

成功了!因此，指令运行时变量未完全准备好似乎是一个问题。它正在查看的 session 对象是通过 resource 创建的，它在获取服务器数据时创建占位符对象，然后填充该对象。

我的猜测是，angular 看到对象存在(实际上是占位符)但我想要的值实际上还不存在。不知道为什么控制台输出显示它们在那里，但是哦，好吧。为了修复它，我向对象添加了一个 watch 语句，该对象在实际更改并被填充时被删除。我的指令现在看起来像这样

LastMeet.directive("progressBar", function($timeout) {
  return {
    restrict: "A",
    scope: {
      meeting: "=meeting"
    },
    link: function(scope, elm, attrs) {

      unwatch = scope.$watch('meeting', function(meeting) {
        if (meeting) {
          // Gather the details we need about this meeting
          var startDate = meeting.start_datetime;
          var deadline  = meeting.deadline;
          var complete  = meeting.percentage_complete;

          // No point doing anything if we're already at 100%      
          if (complete < 100.0) {
            // Calculate how much to increment by every second
            var diff      = deadline - startDate;
            var increment = diff / 60.0;

            var timer;

            scope.percentage = complete;

            scope.onTimeout = function() {

              if (scope.percentage < 100.0) { 
                scope.percentage += increment;
                elm.css({ right: 100 - scope.percentage + "%" });
                timer = $timeout(scope.onTimeout, 1000);
              }

            }

            // Setup our timer and get going :)
            timer = $timeout(scope.onTimeout, 1000);
          }

          unwatch();
        } 
      }, true)
    }
  }
})

现在我有一些计算问题，但它正在工作:)