Is there a way to be more concise when using classMethods in Sequelize?

Question

I have a model intent which has a hasMany association to conditions and links and nodes . The nodes themselves have an association to links as well.

Through an express route I want to get all that information in one object. The way I have done it now is very callbackery and unreadable. It works, but I'm hoping there's a better way to write these kind of things.

app.get('/api/intents/:id', function(req, res) {
    models.intent.findOne({
        where: {
            id: req.params.id
        }
    })
    .then(function(intent) {
        intent.getConditions() // call generated function from intent model for conditions
        .then(function(conditions) {
            intent.getLinks() // then call generated function from intent model for links
            .then(function(links) {
                intent.getNodes() // then call generated function from nodes model for links
                .then(function(nodes) {
                    Promise.map(nodes, function(node) {
                        return node.getLinks() // Even deeper nested and getting out of hand
                        .then(function(links) {
                            node.setDataValue('links', links)
                        })
                    })
                    .then(function() {
                        intent.setDataValue('conditions', conditions)
                        intent.setDataValue('links', links)
                        intent.setDataValue('nodes', nodes)
                        res.json(intent)
                    })
                })
            })
        })
    })
})

Answer 1

I think that you totally missed the conception of include in options object of method like findOne . Just use

models.intent.findById(req.params.id, {
    include: [
        { model: models.condition },
        { model: models.link },
        { model: models.node, include: [ { model: models.link } ]
    ]
}).then((intent) => {
    // here you get intent with conditions, links and nodes with links
});

Other way is to define and use scopes on models.

Answer 2

You can use Promise.all() to wait for all the promises to be resolved and then do something with the data.

Below is a partial example to get you on track:

app.get('/api/intents/:id', function(req, res) {
models.intent.findOne({
    where: {
        id: req.params.id
    }
})
.then(function(intent) {
    let promises = []

    promises.push(intent.getConditions())
    promises.push(intent.getLinks())
    promises.push(intent.getNodes())

    Promise.all(promises)
    .then(function(resolvedPromises) {
        Promise.map(resolvedPromises, function(node) {
            intent.setDataValue('conditions', resolvedPromises[0])
            intent.setDataValue('links', resolvedPromises[1])
            ...
        })
    })
})