Question

我想要实现的是PopUpView只有在保存所有模型后才被调用。

运行代码时，弹出视图会在保存完成之前运行。

var promises = []
_.each(exampleModels, _.bind(function (resource) {
    var filter = this.resources.get(resource.id);
    filter.fetch(
            {
                success: function (model, response) {
                    var participant = new Model({
                        example: "text"
                    });
                    promises.push(participant.save());
                }
            });
}, this));

$.when.apply($, promises).then(_.bind(function () {
    var popupForm = new PopUpView({

    });
    this.$el.append(popupForm.$el);
}, this));

Answer 1

问题是fetch也是异步的。因此，当您点击$.when.apply(...行时，promises是一个空数组。因此when返回的承诺会直接触发then。

Answer 2

您可以model.fetch和model.save

deferred

您可以通过then return a new promise ¹

你可以像这样构建你的承诺数组

var promises = _(ids).chain()
    .map(function(id) {
        // get the models you want 
        return c.get(id);
    })
    .map(function(model) { // build a promise for each model
        return model.fetch(). // promise returned by fetch
            then(function(resp) {
                var participant = new M({
                    example: "text"
                });
                return participant.save(); // promise returned by save
            });
    })
    .value();

$.when.apply($, promises).then(function() {
    console.log('done');
});

演示http://jsfiddle.net/nikoshr/du44m1ha/

¹自jQuery 1.8以来

Jquery Promise Backbone Fetch

2 个答案: