Method _setArrayProperty

packages/helpers/classes/mail.js:659–663

* Set an array property after checking that the new value is an * array.

(propertyName, value)

   * array.
   */
  _setArrayProperty(propertyName, value) {
    if (this._doArrayCheck(propertyName, value)) {
      this[propertyName] = value;
    }
  }

  /**
   * Check that a value isn't undefined and is an array.