猫鼬批量保存/更新与异步每个只更新一些文档

Question

I have a batch update that I am trying to perform using the contents of a user-submitted form. Each submission updates a variable subset of the submitted docs. It seems like the final callback is basically being called before all the async operations complete, but I cannot figure out how to resolve it. I also tried this with async.eachSeries but the error is the same.

    // updates is a list of object ids    
    Items.model.find ({
        _id: {$in: updates}
    })
        .exec (function (err, found) {
            console.log (found);
            // 'found' contains the expected submissions
            for (var i = 0; i < found.length; i++) {
                console.log (found [i]._id);
                found [i].category = ObjectId (req.body [found [i]._id]);
                found [i].state = 'submitted';
            }

            // 'found' now shows the desired updates correctly
            console.log (found);
            async.eachSeries (found, function (item, next) {
                console.log (item);
                //each item appears to contain the desired updates
                item.save (function (err) {
                    if (err) return next (err);
                    return next ();
                });
            }, function (err) {
                console.log (err);
                console.log ("done");
                return res.redirect ('/dataview/' + locals.app.name + "/" + req.body.page);
            });
        });

at the end of all the above, if we revisit the page, only a subset of the docs is actually updated and stored apparently. I'm tearing my hair out trying to figure out why.

Answer 1

You can use async.eachOfSeries to complete in single iteration instead of double

// updates is a list of object ids    
Items.model.find({
        _id: {
            $in: updates
        }
    })
    .exec(function (err, found) {
        console.log(found);
        // 'found' contains the expected submissions
        async.eachOfSeries(found, function (item, i, next) {
            item.category = ObjectId(req.body[item._id]);
            item.state = 'submitted';
            console.log(item);
            //each item appears to contain the desired updates
            item.save(next);
        }, function (err) {
            console.log(err);
            console.log("done");
            return res.redirect('/dataview/' + locals.app.name + "/" + req.body.page);
        });
    });

But I would like to recommend you to use Promise.all function and update directly rather than find and update

const itemList = [];
for (var i = 0; i < updates.length; i++) {
    itemList.push(Items.model.update({
        _id: updates[i]
    }, {
        $set: {
            state: 'submitted',
            category: ObjectId(req.body[updates[i]])
        }
    }));
}
Promise.all(itemList)
    .then((items) => {
        console.log('success');
        return res.redirect('/dataview/' + locals.app.name + '/' + req.body.page);
    })
    .catch((err) => {
        console.log('error ', err);
        return res.redirect('/dataview/' + locals.app.name + '/' + req.body.page);
    });