How to set dynamic value into parent row cell value

I want to set cell value dynamic into parents node.
and for that I am was used

onBeforeCellRender: function (args) {
  if (args.cell.start == DayPilot.Date.today()) {
    args.cell.backColor = "#00639e45";
  }
  if (args.cell.resource === "GB") {
    this.parsentages.map(item => {
      args.cell.areas = [
        {
          backColor: "#cccccc4f",
          top: 0,
          left: 0,
          right: 0,
          bottom: 0,
          text: item,
          style: "text-align: center; color: #333; font-size: 8pt;padding:10px"
        },
      ];
    })
  }
},

But I want to set that 50% dynamic for each day and it's based on API