[charts] Remove redundant default axis

packages/x-charts-pro/src/Heatmap/Heatmap.test.tsx

@@ -23,4 +23,55 @@ describe('<Heatmap /> - License', () => {
 
     expect(await screen.findAllByText('MUI X Missing license key')).not.to.equal(null);
   });
+
+  it('should render "No data to display" when axes are empty arrays', () => {
+    render(<Heatmap series={[]} width={100} height={100} xAxis={[]} yAxis={[]} />);
+
+    expect(screen.getByText('No data to display')).toBeVisible();
+  });
+
+  describe('axis defaults', () => {
+    const series = [
+      {
+        data: [
+          [0, 3, 7],
+          [1, 5, 8],
+        ],
+      },
+    ] as const;
+
+    it('should render default axes when axes are empty arrays and series contain data', () => {
+      render(<Heatmap series={series} width={100} height={100} xAxis={[]} yAxis={[]} />);
+
+      const xAxisTickLabels = screen.getAllByTestId('ChartsXAxisTickLabel');
+      expect(xAxisTickLabels.map((t) => t.textContent)).to.deep.equal(['0', '1']);
+
+      const yAxisTickLabels = screen.getAllByTestId('ChartsYAxisTickLabel');
+      expect(yAxisTickLabels.map((t) => t.textContent)).to.deep.equal([
+        '0',
+        '1',
+        '2',
+        '3',
+        '4',
+        '5',
+      ]);
+    });
+
+    it('should render default axes when axes are an array of an empty object and series contain data', () => {
+      render(<Heatmap series={series} width={100} height={100} xAxis={[{}]} yAxis={[{}]} />);
+
+      const xAxisTickLabels = screen.getAllByTestId('ChartsXAxisTickLabel');
+      expect(xAxisTickLabels.map((t) => t.textContent)).to.deep.equal(['0', '1']);
+
+      const yAxisTickLabels = screen.getAllByTestId('ChartsYAxisTickLabel');
+      expect(yAxisTickLabels.map((t) => t.textContent)).to.deep.equal([
+        '0',
+        '1',
+        '2',
+        '3',
+        '4',
+        '5',
+      ]);
+    });
+  });
 });

packages/x-charts-pro/src/Heatmap/Heatmap.tsx

@@ -22,6 +22,7 @@ import {
   ChartsOverlaySlotProps,
   ChartsOverlaySlots,
 } from '@mui/x-charts/ChartsOverlay';
+import { DEFAULT_X_AXIS_KEY, DEFAULT_Y_AXIS_KEY } from '@mui/x-charts/constants';
 import { ChartContainerPro, ChartContainerProProps } from '../ChartContainerPro';
 import { HeatmapSeriesType } from '../models/seriesType/heatmap';
 import { HeatmapPlot } from './HeatmapPlot';
@@ -100,6 +101,19 @@ const defaultColorMap = interpolateRgbBasis([
 
 const seriesConfig: ChartSeriesConfig<'heatmap'> = { heatmap: heatmapSeriesConfig };
 
+function getDefaultDataForAxis(series: HeatmapProps['series'], dimension: number) {
+  if (series?.[0]?.data === undefined || series[0].data.length === 0) {
+    return [];
+  }
+
+  return Array.from(
+    { length: Math.max(...series[0].data.map((dataPoint) => dataPoint[dimension])) + 1 },
+    (_, index) => index,
+  );
+}
+const getDefaultDataForXAxis = (series: HeatmapProps['series']) => getDefaultDataForAxis(series, 0);
+const getDefaultDataForYAxis = (series: HeatmapProps['series']) => getDefaultDataForAxis(series, 1);
+
 const Heatmap = React.forwardRef(function Heatmap(
   inProps: HeatmapProps,
   ref: React.Ref<SVGSVGElement>,
@@ -129,13 +143,25 @@ const Heatmap = React.forwardRef(function Heatmap(
   const clipPathId = `${id}-clip-path`;
 
   const defaultizedXAxis = React.useMemo(
-    () => xAxis.map((axis) => ({ scaleType: 'band' as const, categoryGapRatio: 0, ...axis })),
-    [xAxis],
+    () =>
+      (xAxis && xAxis.length > 0 ? xAxis : [{ id: DEFAULT_X_AXIS_KEY }]).map((axis) => ({
+        scaleType: 'band' as const,
+        categoryGapRatio: 0,
+        ...axis,
+        data: axis.data ?? getDefaultDataForXAxis(series),
+      })),
+    [series, xAxis],
   );
 
   const defaultizedYAxis = React.useMemo(
-    () => yAxis.map((axis) => ({ scaleType: 'band' as const, categoryGapRatio: 0, ...axis })),
-    [yAxis],
+    () =>
+      (yAxis && yAxis.length > 0 ? yAxis : [{ id: DEFAULT_Y_AXIS_KEY }]).map((axis) => ({
+        scaleType: 'band' as const,
+        categoryGapRatio: 0,
+        ...axis,
+        data: axis.data ?? getDefaultDataForYAxis(series),
+      })),
+    [series, yAxis],
   );
 
   const defaultizedZAxis = React.useMemo(

packages/x-charts/src/BarChart/BarChart.test.tsx

@@ -2,6 +2,8 @@ import * as React from 'react';
 import { createRenderer } from '@mui/internal-test-utils/createRenderer';
 import { describeConformance } from 'test/utils/describeConformance';
 import { BarChart } from '@mui/x-charts/BarChart';
+import { expect } from 'chai';
+import { screen } from '@mui/internal-test-utils';
 
 describe('<BarChart />', () => {
   const { render } = createRenderer();
@@ -28,4 +30,10 @@ describe('<BarChart />', () => {
       ],
     }),
   );
+
+  it('should render "No data to display" when axes are empty arrays', () => {
+    render(<BarChart series={[]} width={100} height={100} xAxis={[]} yAxis={[]} />);
+
+    expect(screen.getByText('No data to display')).toBeVisible();
+  });
 });

packages/x-charts/src/ChartsXAxis/ChartsXAxis.tsx

@@ -278,6 +278,7 @@ function ChartsXAxis(inProps: ChartsXAxisProps) {
               <TickLabel
                 x={xTickLabel}
                 y={yTickLabel}
+                data-testid="ChartsXAxisTickLabel"
                 {...axisTickLabelProps}
                 text={formattedValue.toString()}
               />

packages/x-charts/src/ChartsYAxis/ChartsYAxis.tsx

@@ -208,6 +208,7 @@ function ChartsYAxis(inProps: ChartsYAxisProps) {
               <TickLabel
                 x={xTickLabel}
                 y={yTickLabel}
+                data-testid="ChartsYAxisTickLabel"
                 text={formattedValue.toString()}
                 {...axisTickLabelProps}
               />

packages/x-charts/src/LineChart/LineChart.test.tsx

@@ -2,6 +2,8 @@ import * as React from 'react';
 import { createRenderer } from '@mui/internal-test-utils/createRenderer';
 import { describeConformance } from 'test/utils/describeConformance';
 import { LineChart } from '@mui/x-charts/LineChart';
+import { expect } from 'chai';
+import { screen } from '@mui/internal-test-utils';
 
 describe('<LineChart />', () => {
   const { render } = createRenderer();
@@ -27,4 +29,10 @@ describe('<LineChart />', () => {
       ],
     }),
   );
+
+  it('should render "No data to display" when axes are empty arrays', () => {
+    render(<LineChart series={[]} width={100} height={100} xAxis={[]} yAxis={[]} />);
+
+    expect(screen.getByText('No data to display')).toBeVisible();
+  });
 });

packages/x-charts/src/ScatterChart/ScatterChart.test.tsx

@@ -159,4 +159,10 @@ describe('<ScatterChart />', () => {
     const labelY = await screen.findByText('600');
     expect(labelY).toBeVisible();
   });
+
+  it('should render "No data to display" when axes are empty arrays', () => {
+    render(<ScatterChart series={[]} width={100} height={100} xAxis={[]} yAxis={[]} />);
+
+    expect(screen.getByText('No data to display')).toBeVisible();
+  });
 });

packages/x-charts/src/internals/plugins/featurePlugins/useChartCartesianAxis/defaultizeAxis.ts

@@ -26,9 +26,6 @@ export function defaultizeAxis(
 ): AxisConfig[] {
   const DEFAULT_AXIS_KEY = axisName === 'x' ? DEFAULT_X_AXIS_KEY : DEFAULT_Y_AXIS_KEY;
 
-  const hasNoDefaultAxis =
-    inAxis === undefined || inAxis.findIndex(({ id }) => id === DEFAULT_AXIS_KEY) === -1;
-
   const offsets = {
     top: 0,
     right: 0,
@@ -37,10 +34,10 @@ export function defaultizeAxis(
     none: 0,
   };
 
-  const parsedAxes = [
-    ...(inAxis ?? []),
-    ...(hasNoDefaultAxis ? [{ id: DEFAULT_AXIS_KEY, scaleType: 'linear' as const }] : []),
-  ].map((axisConfig, index) => {
+  const inputAxes =
+    inAxis && inAxis.length > 0 ? inAxis : [{ id: DEFAULT_AXIS_KEY, scaleType: 'linear' as const }];
+
+  const parsedAxes = inputAxes.map((axisConfig, index) => {
     const dataKey = axisConfig.dataKey;
     const defaultPosition = axisName === 'x' ? ('bottom' as const) : ('left' as const);