Blend if parameters

I am making a vanilla plugin to control the layer style blend if parameters with a 4 handle slider.
I need to get existing parameters from the active layer, but I can’t find any references the subject.
It’s only a batchplay script but without references it’s impossible to write.
It would be greatly appreciated if someone can help

Try json property of layer. I think that is the only way now how to read it. It is not ideal.

const {batchPlay} = require("photoshop").action;

const result = await batchPlay(
   [
      {
         _obj: "get",
         _target: [
            {
               _property: "json"
            },
            {
               _ref: "layer",
               _id: 4
            },
            {
               _ref: "document",
               _id: 63
            }
         ],
         _options: {
            dialogOptions: "dontDisplay"
         }
      }
   ],
   {}
);

Thanks, I will try tomorrow