React Why I am getting Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'slice') Error?

Question

I can delete dataValues ​​without any problems, but when I try to delete dataCategories, I get the error Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'slice'). The data I am trying to delete is of the same type for both dataValues ​​and dataCategories;

datasetX: ['var1Value']
datasetY: ['meas1Value']
yAxisData: Array(1)
    0: (5) [2, 10, 4, 20, 8]
xAxisData: Array(1)
    0: (5) [5, 8, 10, 15, 20]

Here is my remove function ;

  const removeThisGroup = (itemToRemove) => {
    const chart = findChartByType(chartData, itemToRemove.chartName);
    const groupId = itemToRemove.id;
    const type = itemToRemove.type;

    if (type === 'dataValues') {
      const indexToRemove = chart.dataValues.findIndex((inputGroup) => inputGroup.key === groupId);

      if (indexToRemove !== -1) {
        chart.data[0].datasetY.splice(indexToRemove, 1);
        chart.data[0].yAxisData.splice(indexToRemove, 1);
      }

      chart.dataValues = chart.dataValues.filter((inputGroup) => inputGroup.key !== groupId);
    } else if (type === 'dataCategories') {

      const indexToRemove = chart.dataCategories.findIndex((inputGroup) => inputGroup.key === groupId);

      if (indexToRemove !== -1) {
        chart.data[0].datasetX.splice(indexToRemove, 1);
        chart.data[0].xAxisData.splice(indexToRemove, 1);
      }
      

      chart.dataCategories = chart.dataCategories.filter((inputGroup) => inputGroup.key !== groupId);
    }

    const chartIndex = chartData.findIndex((c) => c.chartName === chart.chartName);
    const updatedChartData = [...chartData];
    updatedChartData[chartIndex] = chart;

    setChartData(updatedChartData);
  };

I checked the indexToRemove, chart.data[0].datasetX and chart.data[0].xAxisData values ​​and they are correct.