Init sqlite take 2

server/models/PlaylistMediaItem.js

@@ -0,0 +1,82 @@
+const { DataTypes, Model } = require('sequelize')
+
+module.exports = (sequelize) => {
+  class PlaylistMediaItem extends Model {
+    static removeByIds(playlistId, mediaItemId) {
+      return this.destroy({
+        where: {
+          playlistId,
+          mediaItemId
+        }
+      })
+    }
+
+    getMediaItem(options) {
+      if (!this.mediaItemType) return Promise.resolve(null)
+      const mixinMethodName = `get${sequelize.uppercaseFirst(this.mediaItemType)}`
+      return this[mixinMethodName](options)
+    }
+  }
+
+  PlaylistMediaItem.init({
+    id: {
+      type: DataTypes.UUID,
+      defaultValue: DataTypes.UUIDV4,
+      primaryKey: true
+    },
+    mediaItemId: DataTypes.UUIDV4,
+    mediaItemType: DataTypes.STRING,
+    order: DataTypes.INTEGER
+  }, {
+    sequelize,
+    timestamps: true,
+    updatedAt: false,
+    modelName: 'playlistMediaItem'
+  })
+
+  const { book, podcastEpisode, playlist } = sequelize.models
+
+  book.hasMany(PlaylistMediaItem, {
+    foreignKey: 'mediaItemId',
+    constraints: false,
+    scope: {
+      mediaItemType: 'book'
+    }
+  })
+  PlaylistMediaItem.belongsTo(book, { foreignKey: 'mediaItemId', constraints: false })
+
+  podcastEpisode.hasOne(PlaylistMediaItem, {
+    foreignKey: 'mediaItemId',
+    constraints: false,
+    scope: {
+      mediaItemType: 'podcastEpisode'
+    }
+  })
+  PlaylistMediaItem.belongsTo(podcastEpisode, { foreignKey: 'mediaItemId', constraints: false })
+
+  PlaylistMediaItem.addHook('afterFind', findResult => {
+    if (!findResult) return
+
+    if (!Array.isArray(findResult)) findResult = [findResult]
+
+    for (const instance of findResult) {
+      if (instance.mediaItemType === 'book' && instance.book !== undefined) {
+        instance.mediaItem = instance.book
+        instance.dataValues.mediaItem = instance.dataValues.book
+      } else if (instance.mediaItemType === 'podcastEpisode' && instance.podcastEpisode !== undefined) {
+        instance.mediaItem = instance.podcastEpisode
+        instance.dataValues.mediaItem = instance.dataValues.podcastEpisode
+      }
+      // To prevent mistakes:
+      delete instance.book
+      delete instance.dataValues.book
+      delete instance.podcastEpisode
+      delete instance.dataValues.podcastEpisode
+    }
+  })
+
+  playlist.hasMany(PlaylistMediaItem)
+  PlaylistMediaItem.belongsTo(playlist)
+
+  return PlaylistMediaItem
+}