$。当不等待Ajax请求完成时 [英] $.when not waiting for Ajax request to finish

问题描述

我想首先使用Backbone.js呈现一个视图，该视图显示从服务器中提取的文章。然后，我想将此标记为已查看，并将未看到的消息计数返回给路由器，因为它需要可供其他视图使用。

I want to first render a view with Backbone.js that displays an Article pulled from the server. I then want to mark this as "seen" and return the count of unseen messages to the router as it needs to be made available to other views.

所以在我的路由器中，我有：

So in my Router, I have:

    getArticle: function (id) {

        require(["app/models/article", "app/views/Article"], function (models, Article) {

                var article = new models.Article({id: id});

                article.fetch({
                    success: function (data) {

                        var articleView = new Article({model: data, message_count:that.message_count});

                        slider.slidePage(articleView.$el);

                        $.when(articleView.saveView()).done(function(data){
                            console.log('in when and data is ');
                            console.log(data);
                        });

                    },
                    error: function(){
                        console.log('failed to fecth artcie'); 
                    }
                });

        });
    },

文章视图中的saveView（）是：

saveView() in the Article view is:

    saveView: function(){

        var viewDetails = [];

        viewDetails.device_id = this.options.device_id;
        viewDetails.article_id = this.model.id;
        viewDetails.project_title = project_title;

        var article_view = new models.ArticleView();

        article_view.save(viewDetails, 
                        {
                        success: function(data) {
                                var count = data.get('count');   
                                console.log('in saveView() success and count is ');
                                console.log(count); 
                                return count;     
                            },
                            error:   function(model, xhr, options){
                               console.log(xhr.responseText);
                            },
                        });
    },

这会点击REST API，记录文章的查看然后返回一些看不见的文章。这导致控制台输出：

This hits a REST API, records the viewing of the article and then returns a count of unseen Articles. This results in a console output of:

当和数据是router.js时：286 undefined router.js：287 in
saveView（）成功和计数是Article.js：45 4

in when and data is router.js:286 undefined router.js:287 in saveView() success and count is Article.js:45 4

所以，不知何故， $。 无效，因为在执行 .done 脚本之前，它没有等待Ajax请求发送。有任何想法吗？

So, somehow, $.when is not working as it's not waiting for the Ajax request to send before executing the .done script. Any ideas?

推荐答案

你需要返回一个jQuery 延迟 对象 $。当正常工作时：

You need to return a jQuery Deferred object for $.when to work properly:

return article_view.save(viewDetails, 
    {
    success: function(data) {
            var count = data.get('count');   
            console.log('in saveView() success and count is ');
            console.log(count); 
            return count;     
        },
        error:   function(model, xhr, options){
           console.log(xhr.responseText);
        },
    });

Backbone的 save（）方法返回 jqXHR 对象，其行为与与此情况下的 Deferred 对象相同。如上所述，只需将回复链接起来。这应该得到 $。when（）等待请求完成。

Backbone's save() method returns a jqXHR object which behaves the same way as a Deferred object in this case. Simply chain the return call as above. This should get $.when() to wait for the request to finish.

这篇关于$。当不等待Ajax请求完成时的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！