visual-variables.js

  renderer.visualVariables = [
    new OpacityVariable({
      valueExpression: "$feature.pred_percent",
      stops: [
        { value: 40, opacity: 0.3, label: "< 40%" },
        { value: 70, opacity: 1.0, label: "> 70%" }
      ]
    }),
    new SizeVariable({
      valueExpression: "$feature.pred_absolute",
      minDataValue: 100,
      maxDataValue: 15000,
      minSize: "10px",
      maxSize: "40px"
    })
  ];