user3384147 user3384147 - 3 months ago 58
Javascript Question

Recursive include Sequelize?

I have category that can have child categories

And when I'm doing findAll I want to include all of those nested, but I don't know the depth.

var includeCondition = {
include: [
{
model: models.categories,
as:'subcategory', nested: true
}]
};

models.categories.findAll(includeCondition)
.then(function (categories) {
resolve(categories);
})
.catch(function (err) {
reject(err);
})
});


The result brings me only one level nested include.

[
{
dataValues:{

},
subcategory:{
model:{
dataValues:{

}
// no subcategory here
}
}
}
]


Can I somehow make sequalize include those nested subcategories ?

Answer

There are few solutions if found for this first one is more complicated but will give better performance:

This one is about implementing hierarchical data structure in MySQL I like the guide here

http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/

The one that is named The Nested Set Model.

The second solution that I actually implemented by myself is recursive expanding, this one uses lots of mysql requests and I believe can be improved, but it's a fast one and works well. The thing is to use for each category function like this

var expandSubcategories = function (category) {
    return new promise(function (resolve, reject) {
        category.getSubcategories().then(function (subcategories) {
            //if has subcategories expand recursively inner subcategories
            if (subcategories && subcategories.length > 0) {
                var expandPromises = [];
                _.each(subcategories, function (subcategory) {
                    expandPromises.push(expandSubcategories(subcategory));
                });

                promise.all(expandPromises).then(function (expandedCategories) {
                    category.subcategories = [];

                    _.each(expandedCategories, function (expandedCategory) {
                        category.subcategories.push(expandedCategory);
                    }, this);


                    //return self with expanded inner
                    resolve(category);
                });

            } else {
                //if has no subcategories return self
                resolve(category);
            }
        });
    });
};

So it's going through the categories and expanding them recursively.

Maybe this will help someone as well.