javascript - 返回主干函数外的变量

Question

我正在尝试将 profile.toJSON() 返回给一个对象，以便在上述代码之外使用它。我不完全理解主干函数是如何工作的，所以我声明了一个全局变量 obj 并尝试使用 obj = profile.toJSON() 解析数据。当我使用 console.log(obj) 它成功显示我的数据。当我将控制台放在上面的代码之外时，它会返回 underfined。

var obj; 
var ProfileView = Backbone.View.extend(
{       
    el: "#profiles",
    template: _.template($('#profileTemplate').html()),
    render: function(eventName) 
    {
        _.each(this.model.models, function(profile)
        {
            var profileTemplate = this.template(profile.toJSON());  
            obj = profile.toJSON();
            $(this.el).html(profileTemplate);
        }, this);

    return this;
    }           
});

Answer 1

你误会了。预创建模型并将其传递给 View 。不要试图从 View 渲染代码中提取一些东西，它不应该以这种方式使用。

var Profile = Backbone.Model.extend({});
var ProfileCollection = Backbone.Collection.extend({
    model: Profile
});

var ProfileListView = Backbone.View.extend({
    ...
    // Everything render does is rendering
    render: function() {
        this.collection.each(function(model) {
            this.$el.append(
                this.template(model.toJSON);
            );
        }, this);
    }
    ...
});

// Your profile instance is defined outside the view, making 
// it de facto available to outside code
var profile = new Profile({
    name: 'Fere Res',
    rep: 48
});

// The profile we just created gets added to a collection
var profiles = new ProfileCollection([profile]);

// We create the profile list view and pass it the collection
var view = new ProfileListView({collection: profiles});

// When we render the view, the render() code defined above is called.
// You can easily see that all the params/variables it uses are in place
view.render();

// Rendering is done, let's check our model is still available
console.log(profile.toJSON()); // :)