code: function StringField(type, options) {
    Field.call(this, type, options);
    this.arg = new Argument();
  
    this.element = util.createElement(this.document, 'input');
    this.element.type = 'text';
    this.element.classList.add('gcli-field');
  
    this.onInputChange = this.onInputChange.bind(this);
    this.element.addEventListener('keyup', this.onInputChange, false);
  
    this.onFieldChange = util.createEvent('StringField.onFieldChange');
  }
docs: A field that allows editing of strings