fix: path of stacked area series with missing values (#703)

src/chart_types/xy_chart/utils/stacked_series_utils.ts

@@ -29,9 +29,9 @@ export interface StackedValues {
 }
 
 /** @internal */
-export const datumXSortPredicate = (xScaleType: ScaleType) => (a: DataSeriesDatum, b: DataSeriesDatum) => {
+export const datumXSortPredicate = (xScaleType: ScaleType, sortedXValues?: (string | number)[]) => (a: DataSeriesDatum, b: DataSeriesDatum) => {
   if (xScaleType === ScaleType.Ordinal || typeof a.x === 'string' || typeof b.x === 'string') {
-    return 0;
+    return sortedXValues ? sortedXValues.indexOf(a.x) - sortedXValues.indexOf(b.x) : 0;
   }
   return a.x - b.x;
 };
@@ -172,7 +172,8 @@ export function formatStackedDataSeriesValues(
         newData.push(filledSeriesDatum);
       }
     }
-    newData.sort(datumXSortPredicate(xScaleType));
+    const sortedXValues = [...xValues];
+    newData.sort(datumXSortPredicate(xScaleType, sortedXValues));
     return {
       ...ds,
       data: newData,

stories/area/16_test_stacked_with_missing.tsx

@@ -0,0 +1,128 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import React from 'react';
+
+import { Chart, CurveType, AreaSeries, Position, Axis, ScaleType } from '../../src';
+
+export const Example = () => (
+  <Chart className="story-chart">
+    <Axis id="bottom" position={Position.Bottom} />
+    <Axis id="left" position={Position.Left} />
+    <AreaSeries
+      id="path-order"
+      xScaleType={ScaleType.Ordinal}
+      yScaleType={ScaleType.Linear}
+      xAccessor="col-0-3"
+      yAccessors={['col-2-5']}
+      data={data}
+      curve={CurveType.CURVE_CATMULL_ROM}
+      splitSeriesAccessors={['col-1-6']}
+      stackAccessors={['col-1-6']}
+    />
+  </Chart>
+);
+
+const data = [
+  {
+    'col-0-3': 'ZRH',
+    'col-1-6': 'Logstash Airways',
+    'col-2-5': 27,
+  },
+  {
+    'col-0-3': 'ZRH',
+    'col-1-6': 'Kibana Airlines',
+    'col-2-5': 38,
+  },
+  {
+    'col-0-3': 'ZRH',
+    'col-1-6': 'JetBeats',
+    'col-2-5': 26,
+  },
+  {
+    'col-0-3': 'ZRH',
+    'col-1-6': 'ES-Air',
+    'col-2-5': 33,
+  },
+  {
+    'col-0-3': 'YYZ',
+    'col-1-6': 'Kibana Airlines',
+    'col-2-5': 5,
+  },
+  {
+    'col-0-3': 'YYZ',
+    'col-1-6': 'JetBeats',
+    'col-2-5': 7,
+  },
+  {
+    'col-0-3': 'YYZ',
+    'col-1-6': 'ES-Air',
+    'col-2-5': 4,
+  },
+  {
+    'col-0-3': 'YWG',
+    'col-1-6': 'Logstash Airways',
+    'col-2-5': 17,
+  },
+  {
+    'col-0-3': 'YWG',
+    'col-1-6': 'Kibana Airlines',
+    'col-2-5': 19,
+  },
+  {
+    'col-0-3': 'YWG',
+    'col-1-6': 'JetBeats',
+    'col-2-5': 17,
+  },
+  {
+    'col-0-3': 'YUL',
+    'col-1-6': 'Logstash Airways',
+    'col-2-5': 4,
+  },
+  {
+    'col-0-3': 'YUL',
+    'col-1-6': 'Kibana Airlines',
+    'col-2-5': 7,
+  },
+  {
+    'col-0-3': 'YUL',
+    'col-1-6': 'JetBeats',
+    'col-2-5': 4,
+  },
+  {
+    'col-0-3': 'YUL',
+    'col-1-6': 'ES-Air',
+    'col-2-5': 13,
+  },
+  {
+    'col-0-3': 'YOW',
+    'col-1-6': 'Logstash Airways',
+    'col-2-5': 11,
+  },
+  {
+    'col-0-3': 'YOW',
+    'col-1-6': 'Kibana Airlines',
+    'col-2-5': 6,
+  },
+  {
+    'col-0-3': 'YOW',
+    'col-1-6': 'ES-Air',
+    'col-2-5': 14,
+  },
+];

stories/area/area.stories.tsx

@@ -43,3 +43,4 @@ export { Example as stackedGrouped } from './15_stacked_grouped';
 
 export { Example as testLinear } from './11_test_linear';
 export { Example as testTime } from './12_test_time';
+export { Example as testStackedWithMissingValues } from './16_test_stacked_with_missing';