Upserting models using the spread function

upsert.js

// The spread function!

Promise.resolve([thing1, thing2, thing3]).spread((thing1, thing2, thing3) => { /* Do something! */ })

// Upserting a sample Movie model

import Models from 'db/models/index'

updateMovie (movie, params) {
    return this.updateMovieWParams(movie, params).spread(this.upsertTagsForMovie).spread(this.updateMovieInfo).spread((movie, params) => movie)
}

updateMovieWParams (movie, params) {
    const newValues = {
        title: params.title,
        image_url: params.image_url
    }

    return movie.update(newValues).then((movie) => [movie, params])
}

upsertTagsForMovie (movie, params) {
    const tags = params.tags ? params.tags : []
    const addTags = tags.map((t) => {
        return Models.Tag.findOrCreate({ where: { tag: t } }).spread((actualTag, trash) => { return actualTag })
    })

    return Promise.all(addTags).then((syncedTags) => {
        movie.setTags(syncedTags)

        for (const i in syncedTags) {
            syncedTags[i].addMovie(movie)
        }

        return [movie, params]
    })
}

updateMovieInfo (movie, params) {
    return Models.MovieInfo.findOrCreate({ where: { movieId: movie.id }}).spread((info, trash) => {
        return info.update({
            director: params.director,
            runtime: params.runtime,
            genre: params.genre,
            summary: params.summary,
        }).then((info) => {
            return [movie, params]
        })
    })
}

addMovie (params) {
    const newValues = {
        title: params.title,
        image_url: params.image_url,
    }

    Models.Movie.create(newValues).then((movie) => { return [movie, params] }).spread(this.upsertTagsForMovie).spread(this.updateMovieInfo).spread((movie, params) => movie)
}