对不起这个长度,但它让我有点疯狂:
假设我想在加载时获得项目的"标题"和".priority"键值.
首先让我们看看每件事的布局:
$scope.items = $firebase(new Firebase("https://****.firebaseio.com")); $scope.items.$on('loaded', function() { console.log($scope.items); });
有了这个,我们得到:
> Object {$bind: function, $add: function, $save: function, $set: function, $remove: function…} > $add: function (item, cb) { > $bind: function (scope, name) { > $child: function (key) { > $getIndex: function () { > $on: function (type, callback) { > $remove: function (key) { > $save: function (key) { > $set: function (newValue) { > this is my item: Object $$hashKey: "012" $id: "this is my item" $priority: 2884707 title: "this is the title of my item" __proto__: Object > __proto__: Object
看起来不错,让我们尝试抓住优先级:
console.log($scope.items.$child('$priority'));
哎呀:
Uncaught Error: Firebase.child failed: First argument was an invalid path: "$priority". Paths must be non-empty strings and can't contain ".", "#", "$", "[", or "]"
好的,我们暂时跳过这个,只是尝试标题:
console.log($scope.items.$child('title')); > Object {$bind: function, $add: function, $save: function, $set: function, $remove: function…} > $add: function (item, cb) { > $bind: function (scope, name) { > $child: function (key) { > $getIndex: function () { > $on: function (type, callback) { > $remove: function (key) { > $save: function (key) { > $set: function (newValue) { > __proto__: Object
无题.
好的,让我们以不同的方式尝试:
var firstItem = $scope.items.$getIndex()[0]; //returns $ids in order of priority console.log($scope.items.$child(firstItem)); > Object {$bind: function, $add: function, $save: function, $set: function, $remove: function…} > $add: function (item, cb) { > $bind: function (scope, name) { > $child: function (key) { > $getIndex: function () { > $on: function (type, callback) { > $remove: function (key) { > $save: function (key) { > $set: function (newValue) { title: "this is the title of my item" > __proto__: Object
但现在没有优先权!
厨房水槽在计算机时间发誓:
console.log($scope.items.title); > undefined console.log($scope.items[0].title); > Uncaught TypeError: Cannot read property 'title' of undefined console.log(Object.keys($scope.items)); > ["$bind", "$add", "$save", "$set", "$remove", "$child", "$on", "$getIndex"]
我错过了什么?我可以通过做几次掉头来获得'头衔',(弄清楚该项目的$ id是使用'$ getIndex()',抓住第n个项目,然后使用'$ child()'再次打电话),但即便如此也不适合优先考虑.是否有更简单的方法从AngularFire v2中获取关键值?或者以任何方式获得$优先权?
我相信我遇到了同样的问题.希望这与您的经历有关.即:
$scope.items = $firebase(new Firebase("https://xxxxxx.firebaseio.com"));
$scope.items.$on('loaded', function() {
console.log($scope.items['some key']); // this writes undefined to console
});
我注意到的是,如果我不依赖这个事件,这确实有效loaded
.例如在HTML中:
<a href="#" data-ng-click="logItem()">click me</a>
在JS中:
$scope.items = $firebase(new Firebase("https://xxxxxx.firebaseio.com"));
$scope.logItem = function() {
console.log($scope.items['some key']); // this works
}
单击"单击我"链接会按预期将我的项目记录到控制台.
感觉像loaded
时间的集合没有完全填充firebase的基础项目.