code: function() {
      var PROPERTIES =
          [[Blockly.Msg.MATH_IS_EVEN, 'EVEN'],
           [Blockly.Msg.MATH_IS_ODD, 'ODD'],
           [Blockly.Msg.MATH_IS_PRIME, 'PRIME'],
           [Blockly.Msg.MATH_IS_WHOLE, 'WHOLE'],
           [Blockly.Msg.MATH_IS_POSITIVE, 'POSITIVE'],
           [Blockly.Msg.MATH_IS_NEGATIVE, 'NEGATIVE'],
           [Blockly.Msg.MATH_IS_DIVISIBLE_BY, 'DIVISIBLE_BY']];
      this.setColour(Blockly.Blocks.math.HUE);
      this.appendValueInput('NUMBER_TO_CHECK')
          .setCheck('Number');
      var dropdown = new Blockly.FieldDropdown(PROPERTIES, function(option) {
        var divisorInput = (option == 'DIVISIBLE_BY');
        this.sourceBlock_.updateShape_(divisorInput);
      });
      this.appendDummyInput()
          .appendField(dropdown, 'PROPERTY');
      this.setInputsInline(true);
      this.setOutput(true, 'Boolean');
      this.setTooltip(Blockly.Msg.MATH_IS_TOOLTIP);
    }
docs: Block for checking if a number is even, odd, prime, whole, positive,
  negative or if it is divisible by certain number.
  @this Blockly.Block