Question

我是Firebase的新手。我正在尝试使用Angular构建可编辑的TreeView，并将其内容保存到Firebase。内容存储在“树”模型中，该模型包含节点列表，每个节点包含其子节点列表等。

将此对象与FireBase同步的最简单方法是什么？简单的3向绑定是否有效（只需使用。$ bind方法将我的模型绑定到firebase对象）？

这是我的代码。添加节点时，它当前会产生错误：

TypeError: Cannot call method 'push' of undefined

使用Javascript：

angular.module("myApp", ["firebase"]).
controller("TreeController", ['$scope', '$firebase', function ($scope, $firebase) {
    var treeRef = new Firebase("https://flickering-fire-x.firebaseio.com/my-tree");
    $scope.delete = function (data) {
        data.nodes = [];
    };
    $scope.add = function (data) {
        data.nodes.push({
            text: "",
            nodes: []
        });
    };
    // Is this correct: ?
    $scope.remoteTree = $firebase(treeRef);
    $scope.remoteTree.$bind($scope, "tree");
}]);

HTML：

<script type="text/ng-template" id="tree_item_renderer.html">
    <input type = "text" ng-model = "data.text" /> 
    <button ng-click = "add(data)" > Add node </button>
    <button ng-click="delete(data)" ng-show="data.nodes.length > 0">Delete nodes</button >
    <ul> 
        <li ng-repeat = "data in data.nodes"
    ng-include = "'tree_item_renderer.html'" ></li>
    </ul>
</script>
<body ng-app="Application" ng-controller="TreeController">
    <ul>
        <li ng-repeat="data in tree" ng-include="'tree_item_renderer.html'"></li>
    </ul>
</body>

Answer 1

您尝试在添加功能中推送到 undefined 数组。

要避免此错误，您必须先创建数组才能使用它！

angular.module("myApp", ["firebase"]).
controller("TreeController", ['$scope', '$firebase', function ($scope, $firebase) {
    var treeRef = new Firebase("https://flickering-fire-x.firebaseio.com/my-tree");

    data.nodes = [];

    $scope.delete = function (data) {
        data.nodes = [];
    };
    $scope.add = function (data) {
        data.nodes.push({
            text: "",
            nodes: []
        });
    };
    // Is this correct: ?
    $scope.remoteTree = $firebase(treeRef);
    $scope.remoteTree.$bind($scope, "tree");
}]);

这将是工作

Answer 2

我明白了 - 问题在于Firebase不会保存空数组，只是忽略它们。因此add函数应检查data.nodes是否未定义：

$scope.add = function (data) {
    var newNode = {
            text: "",
            nodes: []
        } ;
    if(data.nodes){
        data.nodes.push(newNode);
    }else{
        data.nodes = [newNode];
    }
};

将任意对象（角度模型）同步到firebase的最简单方法是什么？

2 个答案: