Js question: Dynamic attribute (App Connect Extension)

Hello, need an advice related with js..

I'm creating an App Connect Extension, and for learning, a basic one..
It's a QR generator and it's working real fine with static values.

The problem comes when I'm using dynamic values:

This appears to be working:

But if I have to wait an API/SC value, the field gets blank (expected like when nothing defined).
There's an extra step I should implement when we are talking about dynamic attributes? Or it's a pure and only js thing I'm missing?

js code:

dmx.Component("qr-generator", {
    attributes: {
        "qr-data": { type: String, default: "" },
        "qr-size": { type: Number, default: 4 }
    },
    render: function (node) {
        const qrData = this.props["qr-data"];
        const qrSize = this.props["qr-size"];
        if (!qrData) {
            node.innerHTML = "";
            return; 
}
        const qrCode = qrcode(0, "L");
        qrCode.addData(qrData);
        qrCode.make();
        node.innerHTML = qrCode.createImgTag(qrSize);
        //acordarse de borrar:
        console.log(qrData);
    },

    init: function (node) {
        this.render(node);
    }
});

Thanks!

components.hjson

  "attributes": [
    {
      "name": "dmx-qr-generator-qr-data",
      "attributeStartsWith": "dmx-bind",
      "attribute": "qr-data",
      "groupTitle": "Dynamic QR Data",
      "groupIcon": "fa fa-lg fa-database",
      "title": "QR Data (Dynamic)",
      "icon": "fa fa-lg fa-database",
      "display": "fieldset",
      "groupEnabler": true,
      "type": "boolean",
      "show": ["qrDataDynamic"],
      "children": 
      [
        {
          "name": "qrDataDynamic",
          "attributeStartsWith": "dmx-bind",
          "attribute": "qr-data",
          "isValue": true,
          "dataBindings": true,
          "title": "QR Data",
          "type": "text",
          "defaultValue": "",
          "help": "Select data for the QR image",
          "initDisplay": "none"
        }
      ],
      "allowedOn": {
        "dmx-qr-generator": true
      }
    }
  ]