feat: add support for start day of week on MLT axis

e2e/tests/test_cases_stories.test.ts

@@ -107,4 +107,12 @@ test.describe('Test cases stories', () => {
       );
     });
   });
+
+  test.describe('Start day of week', () => {
+    test('should correctly render histogram with start of week as Sunday', async ({ page }) => {
+      await common.expectChartAtUrlToMatchScreenshot(page)(
+        'http://localhost:9001/?path=/story/test-cases--start-day-of-week&globals=toggles.showHeader:true;toggles.showChartTitle:false;toggles.showChartDescription:false;toggles.showChartBoundary:false;theme:light&knob-start date=1710796632334&knob-start dow=7&knob-data count=18&knob-data interval (amount)=1&knob-data interval (unit)=week',
+      );
+    });
+  });
 });

e2e_server/server/mocks/@storybook/addon-knobs/index.ts

@@ -6,6 +6,8 @@
  * Side Public License, v 1.
  */
 
+import moment from 'moment';
+
 function getParams() {
   return new URL(window.location.toString()).searchParams;
 }
@@ -25,6 +27,16 @@ export function number(name: string, dftValue: number, options?: any, groupId?:
   return Number.parseFloat(params.get(key) ?? `${dftValue}`);
 }
 
+export function date(name: string, dftValue: Date, groupId?: string): Date {
+  const params = getParams();
+  const key = getKnobKey(name, groupId);
+  const value = params.get(key);
+  const numValue = parseInt(value ?? '');
+  const dateValue = isNaN(numValue) ? value : numValue;
+
+  return dateValue ? moment(dateValue).toDate() : dftValue;
+}
+
 export function radios(name: string, options: unknown, dftValue: string, groupId?: string) {
   return text(name, dftValue, groupId);
 }

packages/charts/api/charts.api.md

@@ -2708,7 +2708,7 @@ export const Settings: (props: SFProps<SettingsSpec, keyof (typeof settingsBuild
 // Warning: (ae-forgotten-export) The symbol "BuildProps" needs to be exported by the entry point index.d.ts
 //
 // @public (undocumented)
-export const settingsBuildProps: BuildProps<SettingsSpec, "id" | "chartType" | "specType", "debug" | "locale" | "rotation" | "ariaLabelHeadingLevel" | "ariaUseDefaultSummary" | "legendPosition" | "flatLegend" | "legendMaxDepth" | "legendSize" | "showLegend" | "showLegendExtra" | "baseTheme" | "rendering" | "animateData" | "externalPointerEvents" | "pointBuffer" | "pointerUpdateTrigger" | "brushAxis" | "minBrushDelta" | "allowBrushingLastHistogramBin", "ariaDescription" | "ariaLabel" | "xDomain" | "ariaDescribedBy" | "ariaLabelledBy" | "ariaTableCaption" | "theme" | "legendAction" | "legendColorPicker" | "legendStrategy" | "onLegendItemClick" | "customLegend" | "onLegendItemMinusClick" | "onLegendItemOut" | "onLegendItemOver" | "onLegendItemPlusClick" | "orderOrdinalBinsBy" | "debugState" | "onProjectionClick" | "onElementClick" | "onElementOver" | "onElementOut" | "onBrushEnd" | "onPointerUpdate" | "onResize" | "onRenderChange" | "onWillRender" | "onProjectionAreaChange" | "onAnnotationClick" | "resizeDebounce" | "pointerUpdateDebounce" | "roundHistogramBrushValues" | "noResults" | "legendSort", never>;
+export const settingsBuildProps: BuildProps<SettingsSpec, "id" | "chartType" | "specType", "debug" | "locale" | "rotation" | "baseTheme" | "rendering" | "animateData" | "externalPointerEvents" | "pointBuffer" | "pointerUpdateTrigger" | "brushAxis" | "minBrushDelta" | "allowBrushingLastHistogramBin" | "ariaLabelHeadingLevel" | "ariaUseDefaultSummary" | "dow" | "showLegend" | "legendPosition" | "showLegendExtra" | "legendMaxDepth" | "legendSize" | "flatLegend", "ariaDescription" | "ariaLabel" | "xDomain" | "theme" | "debugState" | "onProjectionClick" | "onElementClick" | "onElementOver" | "onElementOut" | "onBrushEnd" | "onPointerUpdate" | "onResize" | "onRenderChange" | "onWillRender" | "onProjectionAreaChange" | "onAnnotationClick" | "resizeDebounce" | "pointerUpdateDebounce" | "roundHistogramBrushValues" | "orderOrdinalBinsBy" | "noResults" | "ariaLabelledBy" | "ariaDescribedBy" | "ariaTableCaption" | "legendStrategy" | "onLegendItemOver" | "onLegendItemOut" | "onLegendItemClick" | "onLegendItemPlusClick" | "onLegendItemMinusClick" | "legendAction" | "legendColorPicker" | "legendSort" | "customLegend", never>;
 
 // @public (undocumented)
 export type SettingsProps = ComponentProps<typeof Settings>;
@@ -2730,6 +2730,7 @@ export interface SettingsSpec extends Spec, LegendSpec {
     debug: boolean;
     // @alpha
     debugState?: boolean;
+    dow: number;
     // @alpha
     externalPointerEvents: ExternalPointerEventsSettings;
     locale: string;

packages/charts/src/chart_types/timeslip/timeslip/config.ts

@@ -90,6 +90,7 @@ export interface TimeslipConfig extends TimeslipTheme, RasterConfig {
 export const rasterConfig: RasterConfig = {
   minimumTickPixelDistance: MINIMUM_TICK_PIXEL_DISTANCE,
   locale: 'en-US',
+  dow: 1,
 };
 
 /** @internal */

packages/charts/src/chart_types/xy_chart/axes/timeslip/chrono/chrono_luxon/chrono_luxon.ts

@@ -6,7 +6,6 @@
  * Side Public License, v 1.
  */
 
-// eslint-disable-next-line import/no-extraneous-dependencies
 import { DateTime } from 'luxon';
 
 /** @internal */

packages/charts/src/chart_types/xy_chart/axes/timeslip/continuous_time_rasters.ts

@@ -81,6 +81,7 @@ export interface AxisLayer<T extends Interval> {
 export interface RasterConfig {
   minimumTickPixelDistance: number;
   locale: string;
+  dow: number;
 }
 
 const millisecondIntervals = (rasterMs: number): IntervalIterableMaker<Interval> =>
@@ -158,7 +159,10 @@ const englishPluralRules = new Intl.PluralRules('en-US', { type: 'ordinal' });
 const englishOrdinalEnding = (signedNumber: number) => englishOrdinalEndings[englishPluralRules.select(signedNumber)];
 
 /** @internal */
-export const continuousTimeRasters = ({ minimumTickPixelDistance, locale }: RasterConfig, timeZone: string) => {
+export const continuousTimeRasters = (
+  { minimumTickPixelDistance, locale, dow: startDayOfWeek }: RasterConfig,
+  timeZone: string,
+) => {
   const minorDayBaseFormat = new Intl.DateTimeFormat(locale, { day: 'numeric', timeZone }).format;
   const minorDayFormat = (d: number) => {
     const numberString = minorDayBaseFormat(d);
@@ -317,8 +321,9 @@ export const continuousTimeRasters = ({ minimumTickPixelDistance, locale }: Rast
           const temporalArgs = { timeZone, year, month, day: dayOfMonth };
           const timePoint = cachedZonedDateTimeFrom(temporalArgs);
           const dayOfWeek = timePoint[TimeProp.DayOfWeek];
-          if (dayOfWeek !== 1) continue;
+          if (dayOfWeek !== startDayOfWeek) continue;
           const binStart = timePoint[TimeProp.EpochSeconds];
+
           if (Number.isFinite(binStart)) {
             const daysFromEnd = daysInMonth - dayOfMonth + 1;
             const supremum = cachedTimeDelta(temporalArgs, 'days', 7);

packages/charts/src/chart_types/xy_chart/axes/timeslip/multilayer_ticks.ts

@@ -48,9 +48,10 @@ export function multilayerAxisEntry(
   scale: ScaleContinuous,
   getMeasuredTicks: GetMeasuredTicks,
   locale: string,
+  dow: number,
 ): Projection {
   const rasterSelector = continuousTimeRasters(
-    { minimumTickPixelDistance: MINIMUM_TICK_PIXEL_DISTANCE, locale },
+    { minimumTickPixelDistance: MINIMUM_TICK_PIXEL_DISTANCE, locale, dow },
     xDomain.timeZone,
   );
   const domainValues = xDomain.domain; // todo consider a property or object type rename
@@ -61,6 +62,7 @@ export function multilayerAxisEntry(
   const domainToS = ((Number(domainValues.at(-1)) || NaN) + domainExtension) / 1000;
   const cartesianWidth = Math.abs(range[1] - range[0]);
   const layers = rasterSelector(notTooDense(domainFromS, domainToS, binWidth, cartesianWidth, MAX_TIME_TICK_COUNT));
+
   let layerIndex = -1;
   const fillLayerTimeslip = (
     layer: number,

packages/charts/src/chart_types/xy_chart/state/selectors/visible_ticks.ts

@@ -220,7 +220,7 @@ export const getVisibleTickSetsSelector = createCustomCachedSelector(
 );
 
 function getVisibleTickSets(
-  { rotation: chartRotation, locale }: Pick<SettingsSpec, 'rotation' | 'locale'>,
+  { rotation: chartRotation, locale, dow }: Pick<SettingsSpec, 'rotation' | 'locale' | 'dow'>,
   joinedAxesData: Map<AxisId, JoinedAxisData>,
   { xDomain, yDomains }: Pick<SeriesDomainsAndData, 'xDomain' | 'yDomains'>,
   smScales: SmallMultipleScales,
@@ -342,6 +342,7 @@ function getVisibleTickSets(
               scale,
               getMeasuredTicks,
               locale,
+              dow,
             ),
           );
         }

packages/charts/src/specs/constants.ts

@@ -167,6 +167,7 @@ export const settingsBuildProps = buildSFProps<SettingsSpec>()(
     pointBuffer: 10,
     ...DEFAULT_LEGEND_CONFIG,
     locale: 'en-US',
+    dow: 1,
   },
 );
 

packages/charts/src/specs/settings.tsx

@@ -638,6 +638,15 @@ export interface SettingsSpec extends Spec, LegendSpec {
    * Unicode Locale Identifier, default `en`
    */
   locale: string;
+
+  /**
+   * Refers to the first day of the week as an index.
+   * Expressed according to [**ISO 8601**](https://en.wikipedia.org/wiki/ISO_week_date)
+   * where `1` is Monday, `2` is Tuesday, ..., `6` is Saturday and `7` is Sunday
+   *
+   * @defaultValue 1 (i.e. Monday)
+   */
+  dow: number;
 }
 
 /**

packages/charts/src/state/selectors/get_settings_spec.ts

@@ -8,9 +8,10 @@
 
 import { getSpecs } from './get_specs';
 import { ChartType } from '../../chart_types';
-import { SpecType, DEFAULT_SETTINGS_SPEC } from '../../specs/constants';
+import { SpecType, DEFAULT_SETTINGS_SPEC, settingsBuildProps } from '../../specs/constants';
 import { SettingsSpec } from '../../specs/settings';
 import { debounce } from '../../utils/debounce';
+import { Logger } from '../../utils/logger';
 import { SpecList } from '../chart_state';
 import { createCustomCachedSelector } from '../create_selector';
 import { getSpecsFromStore } from '../utils';
@@ -25,13 +26,21 @@ export const getSettingsSpecSelector = createCustomCachedSelector([getSpecs], ge
 function getSettingsSpec(specs: SpecList): SettingsSpec {
   const settingsSpecs = getSpecsFromStore<SettingsSpec>(specs, ChartType.Global, SpecType.Settings);
   const spec = settingsSpecs[0];
-  return spec ? handleListenerDebouncing(spec) : DEFAULT_SETTINGS_SPEC;
+  return spec ? validateSpec(spec) : DEFAULT_SETTINGS_SPEC;
 }
 
-function handleListenerDebouncing(settings: SettingsSpec): SettingsSpec {
-  const delay = settings.pointerUpdateDebounce ?? DEFAULT_POINTER_UPDATE_DEBOUNCE;
+function validateSpec(spec: SettingsSpec): SettingsSpec {
+  const delay = spec.pointerUpdateDebounce ?? DEFAULT_POINTER_UPDATE_DEBOUNCE;
 
-  if (settings.onPointerUpdate) settings.onPointerUpdate = debounce(settings.onPointerUpdate, delay);
+  if (spec.onPointerUpdate) {
+    spec.onPointerUpdate = debounce(spec.onPointerUpdate, delay);
+  }
 
-  return settings;
+  if (spec.dow < 1 || spec.dow > 7 || !Number.isInteger(spec.dow)) {
+    Logger.warn(`Settings.dow option must be an integer from 1 to 7, received ${spec.dow}. Using default of 1.`);
+
+    spec.dow = settingsBuildProps.defaults.dow;
+  }
+
+  return spec;
 }

storybook/stories/test_cases/11_start_day_of_week.story.tsx

@@ -0,0 +1,105 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { number, select, date } from '@storybook/addon-knobs';
+import moment from 'moment';
+import React from 'react';
+
+import { Chart, Axis, BarSeries, Position, ScaleType, Settings } from '@elastic/charts';
+import { getRandomNumberGenerator } from '@elastic/charts/src/mocks/utils';
+
+import { ChartsStory } from '../../types';
+
+const rng = getRandomNumberGenerator('chart');
+const randomValues = Array.from({ length: 1000 }).map(() => rng(10, 100));
+
+const dayMapping = {
+  1: 'Monday',
+  2: 'Tuesday',
+  3: 'Wednesday',
+  4: 'Thursday',
+  5: 'Friday',
+  6: 'Saturday',
+  7: 'Sunday',
+};
+
+export const Example: ChartsStory = (_, { title, description }) => {
+  const startDate = date('start date', moment(1710796632334).toDate());
+  const startDow = number('start dow', 1, { min: 1, max: 7, step: 1 });
+  const dataCount = number('data count', 18, { min: 0, step: 1 });
+  const dataIntervalAmount = number('data interval (amount)', 1, { min: 1, step: 1 });
+  const dataIntervaUnit = select<moment.unitOfTime.Base>(
+    'data interval (unit)',
+    ['minute', 'hour', 'day', 'week', 'month', 'year'],
+    'week',
+  );
+
+  moment.updateLocale(moment.locale(), { week: { dow: startDow } });
+
+  const data: { x: number; y: number }[] = [];
+  const start = moment(startDate).startOf('w');
+
+  for (let i = 0; i < dataCount; i++) {
+    data.push({
+      x: start
+        .clone()
+        .add(dataIntervalAmount * i, dataIntervaUnit)
+        .valueOf(),
+      y: randomValues[i],
+    });
+  }
+
+  return (
+    <>
+      <Chart title={title} description={description}>
+        <Settings dow={startDow} />
+        <Axis id="y" title="Count" position={Position.Left} />
+        <Axis
+          id="x"
+          title="Time"
+          position={Position.Bottom}
+          timeAxisLayerCount={2}
+          tickFormat={(d) => moment(d).format('llll')}
+          style={{
+            tickLine: { visible: true, padding: 0 },
+            tickLabel: {
+              alignment: {
+                horizontal: Position.Left,
+                vertical: Position.Bottom,
+              },
+              padding: 0,
+              offset: { x: 0, y: 0 },
+            },
+          }}
+        />
+        <BarSeries
+          enableHistogramMode
+          id="bars"
+          name="amount"
+          xScaleType={ScaleType.Time}
+          xAccessor="x"
+          yAccessors={['y']}
+          data={data}
+        />
+      </Chart>
+      <span style={{ padding: 10 }}>
+        <b>dow:</b> {startDow}
+        {/* @ts-ignore - mapping constrained */}
+        &nbsp;({dayMapping[startDow]!})
+      </span>
+      <span style={{ padding: 10 }}>
+        <b>Start:</b> {start.format('llll')}
+      </span>
+    </>
+  );
+};
+
+Example.parameters = {
+  markdown: `You can set the start day of week on the multilayer time axis by using using the \`Settings.dow\` option.
+  This expects a value between \`1\` (Monday) and \`7\` (Sunday) according to the [**ISO 8601**](https://en.wikipedia.org/wiki/ISO_week_date) specification.`,
+};

storybook/stories/test_cases/test_cases.stories.tsx

@@ -21,3 +21,4 @@ export { Example as testPointsOutsideOfDomain } from './8_test_points_outside_of
 export { Example as duplicateLabelsInPartitionLegend } from './9_duplicate_labels_in_partition_legend.story';
 export { Example as highlighterZIndex } from './10_highlighter_z_index.story';
 export { Example as domainEdges } from './21_domain_edges.story';
+export { Example as startDayOfWeek } from './11_start_day_of_week.story';