Dexie relationship loading plugin

relationships.js

import Dexie from 'dexie'

/**
 * Usage: db.table_a.with('table_a_children', 'parent_id', 'children', 'id')
 *
 * This will return all items from table 'table_a'
 * where each item will have a 'children' array with linked records from 'table_a_children' table
 */
Dexie.addons.push((db) => {
  /**
   * Iterate through all items and collect related records
   *
   * @param table
   * @param column
   * @param asProperty
   * @param searchProperty
   *
   * @returns {Dexie.Promise}
   */
  db.Table.prototype.with = function (table, column, asProperty, searchProperty) {
    return this.toCollection().with(table, column, asProperty, searchProperty)
  }

  /**
   * Iterate through all items and collect related records
   *
   * @param table
   * @param column
   * @param asProperty
   * @param searchProperty
   *
   * @returns {Dexie.Promise}
   */
  db.Collection.prototype.with = function (table, column, asProperty, searchProperty) {
    var self = this

    searchProperty = searchProperty || 'id'

    return new Dexie.Promise((resolve, reject) => {
      self.toArray().then(rows => {
        var length = rows.length

        // loop through all rows and collect all data from the related table
        rows.forEach((row, index) => {
          let load = db._allTables[table]
            .where(column)
            .equals(row[searchProperty])
            .toArray()

          load.then(children => {
            rows[index][asProperty] = children
            // once the collection of related items is done, resolve the promise
            if (index + 1 === length) {
              resolve(rows)
            }
          })
        })
      })
    })
  }
})

export default Dexie