From 23477bc422a19c7d8775bafdf2192c4b06142bb7 Mon Sep 17 00:00:00 2001
From: Frantz Kati <bahdcoder@gmail.com>
Date: Sun, 26 Jul 2020 02:51:41 +0100
Subject: [PATCH] 03-accessible-keyboard-navigation

---
 .../react/src/molecules/Select/Select.tsx     | 64 +++++++++++++++++--
 1 file changed, 58 insertions(+), 6 deletions(-)

diff --git a/packages/react/src/molecules/Select/Select.tsx b/packages/react/src/molecules/Select/Select.tsx
index 5b2dd81..bd4605d 100644
--- a/packages/react/src/molecules/Select/Select.tsx
+++ b/packages/react/src/molecules/Select/Select.tsx
@@ -5,7 +5,9 @@ import Text from '../../atoms/Text'
 const KEY_CODES = {
     ENTER: 13,
     SPACE: 32,
-    DOWN_ARROW: 40
+    DOWN_ARROW: 40,
+    ESC: 27,
+    UP_ARROW: 38
 }
 
 interface SelectOption {
@@ -26,6 +28,30 @@ interface SelectProps {
     renderOption?: (props: RenderOptionProps) => React.ReactNode
 }
 
+const getPreviousOptionIndex = (currentIndex: number|null, options: Array<SelectOption>) => {
+    if (currentIndex === null) {
+        return 0
+    }
+
+    if (currentIndex === 0) {
+        return options.length - 1
+    }
+
+    return currentIndex - 1
+}
+
+const getNextOptionIndex = (currentIndex: number|null, options: Array<SelectOption>) => {
+    if (currentIndex === null) {
+        return 0
+    }
+
+    if (currentIndex === options.length - 1) {
+        return 0
+    }
+
+    return currentIndex + 1
+}
+
 const Select: React.FunctionComponent<SelectProps> = ({ options = [], label = 'Please select an option ...', onOptionSelected: handler, renderOption }) => {
     const [isOpen, setIsOpen] = useState<boolean>(false)
     const [selectedIndex, setSelectedIndex] = useState<null|number>(null)
@@ -59,7 +85,7 @@ const Select: React.FunctionComponent<SelectProps> = ({ options = [], label = 'P
         selectedOption = options[selectedIndex]
     }
 
-    const highlightItem = (optionIndex: number|null) => {
+    const highlightOption = (optionIndex: number|null) => {
         setHighlightedIndex(optionIndex)
     }
 
@@ -70,7 +96,7 @@ const Select: React.FunctionComponent<SelectProps> = ({ options = [], label = 'P
             setIsOpen(true)
 
             // set focus on the list item
-            highlightItem(0)
+            highlightOption(0)
         }
     }
 
@@ -86,7 +112,29 @@ const Select: React.FunctionComponent<SelectProps> = ({ options = [], label = 'P
                 ref.current.focus()
             }
         }
-    }, [isOpen])
+    }, [isOpen, highlightedIndex])
+
+    const onOptionKeyDown: KeyboardEventHandler = (event) => {
+        if (event.keyCode === KEY_CODES.ESC) {
+            setIsOpen(false)
+
+            return
+        }
+
+        if (event.keyCode === KEY_CODES.DOWN_ARROW) {
+            highlightOption(getNextOptionIndex(highlightedIndex, options))
+        }
+
+        if (event.keyCode === KEY_CODES.UP_ARROW) {
+            highlightOption(
+                getPreviousOptionIndex(highlightedIndex, options)
+            )
+        }
+
+        if (event.keyCode === KEY_CODES.ENTER) {
+            onOptionSelected(options[highlightedIndex!], highlightedIndex!)
+        }
+    }
 
     return <div className='dse-select'>
         <button onKeyDown={onButtonKeyDown} aria-controls='dse-select-list' aria-haspopup={true} aria-expanded={isOpen ? true: undefined} ref={labelRef} className='dse-select__label' onClick={() => onLabelClick()}>
@@ -109,9 +157,13 @@ const Select: React.FunctionComponent<SelectProps> = ({ options = [], label = 'P
                         isSelected,
                         getOptionRecommendedProps: (overrideProps = {}) => {return {
                             ref,
+                            role: 'menuitemradio',
+                            'aria-label': option.label,
+                            'aria-checked': isSelected ? true : undefined,
+                            onKeyDown: onOptionKeyDown,
                             tabIndex: isHighlighted ? -1 : 0,
-                            onMouseEnter: () => highlightItem(optionIndex),
-                            onMouseLeave: () => highlightItem(null),
+                            onMouseEnter: () => highlightOption(optionIndex),
+                            onMouseLeave: () => highlightOption(null),
                             className: `dse-select__option
                                 ${isSelected ? 'dse-select__option--selected' : ''}
                                 ${isHighlighted ? 'dse-select__option--highlighted' : ''}