blocks/smp.js

Blockly.Blocks['t2n'] = {
  init: function() {
    this.jsonInit({
      //"message0": 'T2N %1',
      "message0": "%{BKY_CONV_TEXT_2_NUMBER} %1",
      "args0": [
        {
          "type": "input_value",
          "name": "VALUE",
          "check": "String"
        }
      ],
      "output": "Number",
      "colour": 200,
      "tooltip": "%{BKY_CONV_TEXT_2_NUMBER_TOOLTIP}",
      "helpUrl": ""
    });
  }
};

generators/javascript/smp.js

Blockly.JavaScript['t2n'] = function(block) {
  var functionName = Blockly.JavaScript.provideFunction_(
    'CatchString',
          ['function ' + Blockly.JavaScript.FUNCTION_NAME_PLACEHOLDER_ +
              '(myStr) {',
            '  return Number(myStr) ;',
            '}']);
   InStr = Blockly.JavaScript.valueToCode(block, 'VALUE', Blockly.JavaScript.ORDER_ATOMIC) || '-99999';
   var arg0 = functionName + '(' + InStr + ')';
   var order = arg0 >= 0 ? Blockly.JavaScript.ORDER_ATOMIC : Blockly.JavaScript.ORDER_UNARY_NEGATION;

   return [arg0,order];
};

msg/js/zh-hant.js

Blockly.Msg["CONV_TEXT_2_NUMBER"] = "字串轉成數字";
Blockly.Msg["CONV_TEXT_2_NUMBER_TOOLTIP"] = "將字串轉換為數字";

msg/js/en.js

Blockly.Msg["CONV_TEXT_2_NUMBER"] = "ConvText2Num";
Blockly.Msg["CONV_TEXT_2_NUMBER_TOOLTIP"] = "Convert String to Number";

index.html

  <script src="./blockly_compressed.js"></script>

  <script src="./blocks/smp.js"></script>
  <script src="./blocks_compressed.js"></script>
  
  <script src="./javascript_compressed.js"></script>  
  <script src="./generators/javascript/smp.js"></script>
  
  <script src="./python_compressed.js"></script>
  <script src="./php_compressed.js"></script>
  <!--  <script src="./msg/zh-hant.js"></script>  -->
    <script src="./msg/en.js"></script>

toolbox.xml

  <category name="EXTLIB">
    <block type="t2n">    </block>
  </category>