Question

为什么我的第一个。然后没有坚持承诺，因为它没有返回任何东西？在以下函数中，控制台显示： blablabla ...... ID列表

暗示第二个。然后在第一个之前执行。

    Model.collection().query(...).fetch().then(function(result) {
        // result is a list of models.
        // I want to run a promise on each of these models in order to add stuff to them
        result.each(function(model) {
            New promise based task on model with .then(function(r) {
                console.log(model.id);
                // with something like:
                model.set('newvalue', r.value);
            });
        });
    }).then(function(result) {
        console.log('blablabla');
        return res.json(result.toJSON());
    }).catch(next);
};

Answer 1

你可能想要使用Bookshelf的collection.mapThen，像这样：

SomeModel.collection().fetch()
.then(function(collection) {
    // collection is a bookshelf collection object
    // collection.mapThen returns a promise
    return collection.mapThen(function(model) {
        console.log("model " + model.id);
        // we can return another promise inside here, and the .mapThen promise 
        // won't be resolved until this one is.
        return knex('users').where({id: model.get('user_id')}).first()
        .then(function(u) {
            model.set('userName', u.user_name);
            // return model as the result of the map.
            return model;
        });
    })
})
.then(function(results) {
    // results is a list of all the modified models
    console.log('blablabla');
    return res.json(results);
})
.catch(next);

等待.then的内容在承诺结束之前返回

1 个答案: