chore(ui-calendar): add keyboard navigation and focus controll for cale…

packages/ui-calendar/src/Calendar/index.tsx

@@ -23,7 +23,14 @@
  */
 
 /** @jsx jsx */
-import React, { Children, Component, ReactElement, MouseEvent } from 'react'
+import React, {
+  Children,
+  Component,
+  ReactElement,
+  MouseEvent,
+  KeyboardEvent,
+  FocusEvent
+} from 'react'
 
 import { View } from '@instructure/ui-view'
 import {
@@ -82,6 +89,9 @@ class Calendar extends Component<CalendarProps, CalendarState> {
     role: 'table'
   }
 
+  // Create ref for each calendar day for programmatic focus management
+  dayRefs: (HTMLElement | null )[]
+
   ref: Element | null = null
   private _weekdayHeaderIds = (
     this.props.renderWeekdayLabels || this.defaultWeekdays
@@ -90,6 +100,7 @@ class Calendar extends Component<CalendarProps, CalendarState> {
   }, {})
   constructor(props: CalendarProps) {
     super(props)
+    this.dayRefs = []
 
     this.state = this.calculateState(
       this.locale(),
@@ -98,10 +109,79 @@ class Calendar extends Component<CalendarProps, CalendarState> {
     )
   }
 
+  setFirstDayTabIndex = (tabIndex: 0 | -1) => {
+    // Manage the first day as the focus entry point and prevent focus 
+    // from getting stuck by adjusting its tabIndex when focus moves to other days
+    if (this.dayRefs[0]) {
+      this.dayRefs[0].tabIndex = tabIndex
+    }
+  }
+
   handleRef = (el: Element | null) => {
     this.ref = el
   }
 
+  handleDaysTableBlur = (e: FocusEvent<Element>) => {
+    const dataCid = e.relatedTarget?.getAttribute('data-cid')
+
+    // If the focus leave the days table,
+    // reset the table focus entry point to its first calendar day
+    if (dataCid !== 'Day') {
+      this.setFirstDayTabIndex(0)
+    }
+  }
+
+  handleKeyDown = (e: KeyboardEvent<Element>, dayIndex: number) => {
+    const totalDays = Calendar.DAY_COUNT
+    const daysPerWeek = 7
+    let targetIndex: number
+
+    const moveFocus = (targetIndex: number) => {
+      const targetDay = this.dayRefs[targetIndex]
+
+      targetDay?.focus()
+      this.setFirstDayTabIndex(-1)
+    }
+
+    switch (e.key) {
+      case 'ArrowLeft':
+        e.preventDefault()
+        targetIndex =
+          dayIndex % daysPerWeek === 0
+            ? dayIndex + daysPerWeek - 1
+            : dayIndex - 1
+        moveFocus(targetIndex)
+        break
+
+      case 'ArrowRight':
+        e.preventDefault()
+        targetIndex =
+          (dayIndex + 1) % daysPerWeek === 0
+            ? dayIndex - (daysPerWeek - 1)
+            : dayIndex + 1
+        moveFocus(targetIndex)
+        break
+
+      case 'ArrowUp':
+        e.preventDefault()
+        targetIndex =
+          dayIndex < daysPerWeek
+            ? dayIndex + totalDays - daysPerWeek
+            : dayIndex - daysPerWeek
+        moveFocus(targetIndex)
+        break
+
+      case 'ArrowDown':
+        e.preventDefault()
+        targetIndex =
+          dayIndex >= totalDays - daysPerWeek
+            ? dayIndex - totalDays + daysPerWeek
+            : dayIndex + daysPerWeek
+        moveFocus(targetIndex)
+        break
+    }
+  }
+
   componentDidMount() {
     this.props.makeStyles?.()
   }
@@ -115,8 +195,9 @@ class Calendar extends Component<CalendarProps, CalendarState> {
       prevProps.visibleMonth !== this.props.visibleMonth
 
     if (isUpdated) {
-      this.setState(() => {
+      this.setState((prevState) => {
         return {
+          ...prevState,
           ...this.calculateState(
             this.locale(),
             this.timezone(),
@@ -347,7 +428,12 @@ class Calendar extends Component<CalendarProps, CalendarState> {
     return (
       <table role={this.role}>
         <thead>{this.renderWeekdayHeaders()}</thead>
-        <tbody>{this.renderDays()}</tbody>
+        {/* eslint-disable-next-line jsx-a11y/no-noninteractive-element-interactions */}
+        <tbody
+          onBlur={(e) => this.handleDaysTableBlur(e)}
+        >
+          {this.renderDays()}
+        </tbody>
       </table>
     )
   }
@@ -433,17 +519,27 @@ class Calendar extends Component<CalendarProps, CalendarState> {
         days[index].push(day)
         return days // 7xN 2D array of `Day`s
       }, [])
-      .map((row) => (
+      .map((row, rowIndex) => (
         <tr key={`row${row[0].props.date}`} role={role}>
-          {row.map((day, i) => (
-            <td key={day.props.date} role={role}>
-              {role === 'presentation'
-                ? safeCloneElement(day, {
-                    'aria-describedby': this._weekdayHeaderIds[i]
-                  })
-                : day}
-            </td>
-          ))}
+          {row.map((day, i) => {
+            const dayIndex = rowIndex * 7 + i
+
+            return (
+              <td
+                key={day.props.date}
+                role={role}
+              >
+                {role === 'presentation'
+                  ? safeCloneElement(day, {
+                      'aria-describedby': this._weekdayHeaderIds[i],
+                      tabIndex: dayIndex === 0 ? 0 : -1,
+                    })
+                  : safeCloneElement(day, {
+                      tabIndex: dayIndex === 0 ? 0 : -1,
+                    })}
+              </td>
+            )
+          })}
         </tr>
       ))
   }
@@ -468,6 +564,8 @@ class Calendar extends Component<CalendarProps, CalendarState> {
 
   // date is returned as an ISO string, like 2021-09-14T22:00:00.000Z
   handleDayClick = (event: MouseEvent<any>, { date }: { date: string }) => {
+    this.setFirstDayTabIndex(-1)
+
     if (this.props.onDateSelected) {
       const parsedDate = DateTime.parse(date, this.locale(), this.timezone())
       this.props.onDateSelected(parsedDate.toISOString(), parsedDate, event)
@@ -490,6 +588,10 @@ class Calendar extends Component<CalendarProps, CalendarState> {
     return disabledDates(date.toISOString())
   }
 
+  setDayRef = (index: number) => (el: Element | null) => {
+    this.dayRefs[index] = el as HTMLElement | null
+  }
+
   renderDefaultdays() {
     const { selectedDate } = this.props
     const { visibleMonth, today } = this.state
@@ -519,8 +621,9 @@ class Calendar extends Component<CalendarProps, CalendarState> {
 
       currDate.add({days: 1})
     }
-    return arr.map((date) => {
+    return arr.map((date, dayIndex) => {
       const dateStr = date.toISOString()
+
       return (
         <Calendar.Day
           key={dateStr}
@@ -531,6 +634,8 @@ class Calendar extends Component<CalendarProps, CalendarState> {
           label={date.format('D MMMM YYYY')} // used by screen readers
           onClick={this.handleDayClick}
           interaction={this.isDisabledDate(date) ? 'disabled' : 'enabled'}
+          elementRef={this.setDayRef(dayIndex)}
+          onKeyDown={(e) => this.handleKeyDown(e, dayIndex)}
         >
           {date.format('DD')}
         </Calendar.Day>

packages/ui-date-input/src/DateInput/__new-tests__/DateInput.test.tsx

@@ -740,8 +740,12 @@ describe('<DateInput />', () => {
       expect(prevMonthButton).toHaveAttribute('tabIndex', '-1')
       expect(calendarDays).toHaveLength(42)
 
-      calendarDays.forEach((day) => {
-        expect(day).toHaveAttribute('tabIndex', '-1')
+      calendarDays.forEach((day, index) => {
+        if (index === 0) {
+          expect(day).toHaveAttribute('tabIndex', '0')
+        } else {
+          expect(day).toHaveAttribute('tabIndex', '-1')
+        }
       })
     })