code: function() {
      this.appendDummyInput()
          .appendField('dropdown')
          .appendField(new Blockly.FieldTextInput('NAME'), 'FIELDNAME');
      this.optionCount_ = 3;
      this.updateShape_();
      this.setPreviousStatement(true, 'Field');
      this.setNextStatement(true, 'Field');
      this.setMutator(new Blockly.Mutator(['field_dropdown_option']));
      this.setColour(160);
      this.setTooltip('Dropdown menu with a list of options.');
      this.setHelpUrl('https://www.youtube.com/watch?v=s2_xaEvcVI0#t=386');
    }
docs: Dropdown menu.