formatter() {
    if (!this._formatter) {
      this._formatter = new Formatter();
      const maximumLengthString = this.element.getAttribute('maxlength');
      if (maximumLengthString !== undefined && maximumLengthString !== null) {
        this._formatter.maximumLength = parseInt(maximumLengthString, 10);
      }
    }

    return this._formatter;
  }
Gets the current formatter. Formatters are used to translate between text
and value properties of the field.

@returns {Formatter}