如何从Firebase数据库中删除项目？

Question

我在反应中创建了一个简单的待办事项，我想在待办事项中删除所选任务。但是，当我运行此代码并尝试删除任何任务时，它会出错：

  

firebase.child失败：第一个参数是无效路径：＆＃34; undefined＆＃34;

componentWillMount: function() {
        this.firebaseRef = new Firebase('https://simpletodosapp.firebaseio.com/todos');
        var that = this;
        this.firebaseRef.once('value', function(snapshot){

            snapshot.forEach(function(data){
                var todos = data.val();
                todos['key'] = data.key;
                that.setState({tasks: todos})
            })
        });
    },

  handleTodo: function(text) {
        var newTask  = this.state.tasks.concat(text)
        this.firebaseRef.push(newTask)
       this.setState({tasks: newTask})

    },

    handleDelete: function(task_id, key) {
        this.firebaseRef.child(key).remove();
        var remove = this.state.tasks.splice(task_id, 1);
        this.setState({itasks: remove})

    },