code: function() {
      this.jsonInit({
        "message0": "%1",
        "args0": [
          {
            "type": "field_dropdown",
            "name": "CONSTANT",
            "options": [
              ['\u03c0', 'PI'],
              ['e', 'E'],
              ['\u03c6', 'GOLDEN_RATIO'],
              ['sqrt(2)', 'SQRT2'],
              ['sqrt(\u00bd)', 'SQRT1_2'],
              ['\u221e', 'INFINITY']
            ]
          }
        ],
        "output": "Number",
        "colour": Blockly.Blocks.math.HUE,
        "tooltip": Blockly.Msg.MATH_CONSTANT_TOOLTIP,
        "helpUrl": Blockly.Msg.MATH_CONSTANT_HELPURL
      });
    }
docs: Block for constants: PI, E, the Golden Ratio, sqrt(2), 1/sqrt(2), INFINITY.
  @this Blockly.Block