Adonis JSONAPI serializer

JsonAPISerializer.js

'use strict'

const _ = use('lodash')

/**
 * JSONAPI serializer for lucid models.
 *
 * NOTE: The implementation is not complete yet.
 *
 * @class JsonAPISerializer
 * @constructor
 */
class JsonAPISerializer {
  constructor (rows, pages, isOne = false) {
    this.rows = rows
    this.pages = pages
    this.isOne = isOne
  }

  /**
   * Attaches relationships to the output row
   *
   * @method _attachRelations
   *
   * @param  {Model}         modelInstance
   * @param  {Object}         output
   *
   * @return {void}
   *
   * @private
   */
  _attachRelations (modelInstance, output) {
    _.each(modelInstance.$relations, (values, relation) => {
      output[relation] = values && typeof (values.toJSON) === 'function' ? values.toJSON() : values
    })

    /**
     * Set an array of relationships added to the JSON. This is
     * required by the `jsona` library itself
     */
    output.relationshipNames = _.keys(modelInstance.$relations)
  }

  /**
   * Serializes a single model instance to a JSON API resource
   *
   * @method _serialize
   *
   * @param  {Model}   modelInstance
   *
   * @return {Object}
   *
   * @private
   */
  _serialize (modelInstance) {
    const json = _.transform(modelInstance.toObject(), (result, value, key) => {
      result[_.kebabCase(key)] = value
      return result
    }, {})

    this._attachRelations(modelInstance, json)

    /**
     * Setting type on the output json row. This is required
     * as per JSON API specs
     */
    json.type = modelInstance.constructor.resourceName || _.kebabCase(modelInstance.constructor.table)
    return json
  }

  /**
   * Add a new row to existing rows
   *
   * @method addRow
   *
   * @param  {Object} row
   */
  addRow (row) {
    this.rows.push(row)
  }

  /**
   * Returns the length of rows
   *
   * @method size
   *
   * @return {Number}
   */
  size () {
    return this.rows.length
  }

  /**
   * Returns the first row
   *
   * @method first
   *
   * @return {Object}
   */
  first () {
    return this.rows[0]
  }

  /**
   * Returns the last row
   *
   * @method last
   *
   * @return {Object}
   */
  last () {
    return this.rows[this.rows.length - 1]
  }

  /**
   * Returns the serialized json
   *
   * @method toJSON
   *
   * @return {Array|Null}
   */
  toJSON () {
    if (this.isOne) {
      return this._serialize(this.rows)
    }
    return this.rows.map((row) => this._serialize(row))
  }
}

module.exports = JsonAPISerializer