[Chartjs]-Chart.js 3.5: linear gradient doesn't apply properly when multiple bars in the same chart

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You need to define this line let width, height, gradient; within your function so its bound to the function and wont get overriden then it works just fine:

const getGradient = (ctx, chartArea, start_color, stop_color) => {
  let width, height, gradient;
  const chartWidth = chartArea.right - chartArea.left;
  const chartHeight = chartArea.bottom - chartArea.top;
  if (gradient === null || width !== chartWidth || height !== chartHeight) {
    // Create the gradient because this is either the first render
    // or the size of the chart has changed
    width = chartWidth;
    height = chartHeight;
    gradient = ctx.createLinearGradient(0, chartArea.bottom, 0, chartArea.top);
    gradient.addColorStop(0, stop_color);
    gradient.addColorStop(1, start_color);
  }
  return gradient;
}

var ctx = document.getElementById("myChart");
var myChart = new Chart(ctx, {
  type: 'bar',
  data: {
    labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
    datasets: [{
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 3],
        backgroundColor: function(context) {
          const chart = context.chart;
          const {
            ctx,
            chartArea
          } = chart;
          if (!chartArea) {
            return null;
          }
          return getGradient(ctx, chartArea, "rgba(182, 86, 235, 1)", "rgba(182, 86, 235, 0.66)");
        }
      },
      {
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 3],
        backgroundColor: function(context) {
          const chart = context.chart;
          const {
            ctx,
            chartArea
          } = chart;
          if (!chartArea) {
            return null;
          }
          return getGradient(ctx, chartArea, "rgba(244, 102, 235, 1)", "rgba(244, 102, 235, 0.66)");
        }
      }
    ]
  },
  options: {
  }
});
<script src="https://npmcdn.com/chart.js@3.9.1/dist/chart.min.js"></script>
<div class="myChartDiv">
  <canvas id="myChart" width="600" height="400"></canvas>
</div>

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