fix(hooks): check state chage via deep compare

docusaurus/pages/useMultipleCombobox.js

@@ -125,7 +125,7 @@ export default function DropdownMultipleCombobox() {
                 style={{padding: '4px', cursor: 'pointer'}}
                 onClick={e => {
                   e.stopPropagation()
-                  removeSelectedItem(null)
+                  removeSelectedItem(selectedItemForRender)
                 }}
               >
                 ✕

src/hooks/__tests__/utils.test.js

@@ -5,6 +5,7 @@ import {
   getDefaultValue,
   useMouseAndTouchTracker,
   getItemAndIndex,
+  isDropdownsStateEqual,
 } from '../utils'
 
 describe('utils', () => {
@@ -152,4 +153,37 @@ describe('utils', () => {
       })
     })
   })
+
+  describe('isDropdownsStateEqual', () => {
+    test('is true when each property is equal', () => {
+      const selectedItem = 'hello'
+      const prevState = {
+        highlightedIndex: 2,
+        isOpen: true,
+        selectedItem,
+        inputValue: selectedItem,
+      }
+      const newState = {
+        ...prevState,
+      }
+
+      expect(isDropdownsStateEqual(prevState, newState)).toBe(true)
+    })
+
+    test('is false when at least one property is not equal', () => {
+      const selectedItem = {value: 'hello'}
+      const prevState = {
+        highlightedIndex: 2,
+        isOpen: true,
+        selectedItem,
+        inputValue: selectedItem,
+      }
+      const newState = {
+        ...prevState,
+        selectedItem: {...selectedItem},
+      }
+
+      expect(isDropdownsStateEqual(prevState, newState)).toBe(false)
+    })
+  })
 })

src/hooks/useCombobox/index.js

@@ -11,6 +11,7 @@ import {
   useElementIds,
   getItemAndIndex,
   getInitialValue,
+  isDropdownsStateEqual
 } from '../utils'
 import {
   getInitialState,
@@ -43,6 +44,7 @@ function useCombobox(userProps = {}) {
     downshiftUseComboboxReducer,
     props,
     getInitialState,
+    isDropdownsStateEqual
   )
   const {isOpen, highlightedIndex, selectedItem, inputValue} = state
 

src/hooks/useCombobox/utils.js

@@ -58,14 +58,16 @@ const propTypes = {
  * @param {Function} reducer Reducer function from downshift.
  * @param {Object} props The hook props, also passed to createInitialState.
  * @param {Function} createInitialState Function that returns the initial state.
+ * @param {Function} isStateEqual Function that checks if a previous state is equal to the next.
  * @returns {Array} An array with the state and an action dispatcher.
  */
-export function useControlledReducer(reducer, props, createInitialState) {
+export function useControlledReducer(reducer, props, createInitialState, isStateEqual) {
   const previousSelectedItemRef = useRef()
   const [state, dispatch] = useEnhancedReducer(
     reducer,
     props,
     createInitialState,
+    isStateEqual
   )
 
   // ToDo: if needed, make same approach as selectedItemChanged from Downshift.

src/hooks/useMultipleSelection/index.js

@@ -14,6 +14,7 @@ import {
   defaultProps,
   isKeyDownOperationPermitted,
   validatePropTypes,
+  isStateEqual
 } from './utils'
 import downshiftMultipleSelectionReducer from './reducer'
 import * as stateChangeTypes from './stateChangeTypes'
@@ -40,6 +41,7 @@ function useMultipleSelection(userProps = {}) {
     downshiftMultipleSelectionReducer,
     props,
     getInitialState,
+    isStateEqual
   )
   const {activeIndex, selectedItems} = state
 

src/hooks/useMultipleSelection/utils.js

@@ -95,6 +95,21 @@ function getA11yRemovalMessage(selectionParameters) {
   return `${itemToStringLocal(removedSelectedItem)} has been removed.`
 }
 
+/**
+ * Check if a state is equal for taglist, by comparing active index and selected items.
+ * Used by useSelect and useCombobox.
+ *
+ * @param {Object} prevState
+ * @param {Object} newState
+ * @returns {boolean} Wheather the states are deeply equal.
+ */
+function isStateEqual(prevState, newState) {
+  return (
+    prevState.selectedItems === newState.selectedItems &&
+    prevState.activeIndex === newState.activeIndex
+  )
+}
+
 const propTypes = {
   ...commonPropTypes,
   selectedItems: PropTypes.array,
@@ -133,4 +148,5 @@ export {
   getDefaultValue,
   getInitialState,
   isKeyDownOperationPermitted,
+  isStateEqual,
 }

src/hooks/useSelect/index.js

@@ -12,6 +12,7 @@ import {
   useMouseAndTouchTracker,
   getItemAndIndex,
   getInitialValue,
+  isDropdownsStateEqual,
 } from '../utils'
 import {
   callAllEventHandlers,
@@ -46,9 +47,9 @@ function useSelect(userProps = {}) {
     downshiftSelectReducer,
     props,
     getInitialState,
+    isDropdownsStateEqual,
   )
   const {isOpen, highlightedIndex, selectedItem, inputValue} = state
-
   // Element efs.
   const toggleButtonRef = useRef(null)
   const menuRef = useRef(null)

src/hooks/utils.js

@@ -189,9 +189,10 @@ function useLatestRef(val) {
  * @param {Function} reducer Reducer function from downshift.
  * @param {Object} props The hook props, also passed to createInitialState.
  * @param {Function} createInitialState Function that returns the initial state.
+ * @param {Function} isStateEqual Function that checks if a previous state is equal to the next.
  * @returns {Array} An array with the state and an action dispatcher.
  */
-function useEnhancedReducer(reducer, props, createInitialState) {
+function useEnhancedReducer(reducer, props, createInitialState, isStateEqual) {
   const prevStateRef = useRef()
   const actionRef = useRef()
   const enhancedReducer = useCallback(
@@ -219,7 +220,12 @@ function useEnhancedReducer(reducer, props, createInitialState) {
   const action = actionRef.current
 
   useEffect(() => {
-    if (action && prevStateRef.current && prevStateRef.current !== state) {
+    const shouldCallOnChangeProps =
+      action &&
+      prevStateRef.current &&
+      !isStateEqual(prevStateRef.current, state)
+
+    if (shouldCallOnChangeProps) {
       callOnChangeProps(
         action,
         getState(prevStateRef.current, action.props),
@@ -228,7 +234,7 @@ function useEnhancedReducer(reducer, props, createInitialState) {
     }
 
     prevStateRef.current = state
-  }, [state, props, action])
+  }, [state, action, isStateEqual])
 
   return [state, dispatchWithProps]
 }
@@ -240,13 +246,20 @@ function useEnhancedReducer(reducer, props, createInitialState) {
  * @param {Function} reducer Reducer function from downshift.
  * @param {Object} props The hook props, also passed to createInitialState.
  * @param {Function} createInitialState Function that returns the initial state.
+ * @param {Function} isStateEqual Function that checks if a previous state is equal to the next.
  * @returns {Array} An array with the state and an action dispatcher.
  */
-function useControlledReducer(reducer, props, createInitialState) {
+function useControlledReducer(
+  reducer,
+  props,
+  createInitialState,
+  isStateEqual,
+) {
   const [state, dispatch] = useEnhancedReducer(
     reducer,
     props,
     createInitialState,
+    isStateEqual,
   )
 
   return [getState(state, props), dispatch]
@@ -585,6 +598,23 @@ function getChangesOnSelection(props, highlightedIndex, inputValue = true) {
   }
 }
 
+/**
+ * Check if a state is equal for dropdowns, by comparing isOpen, inputValue, highlightedIndex and selected item.
+ * Used by useSelect and useCombobox.
+ *
+ * @param {Object} prevState
+ * @param {Object} newState
+ * @returns {boolean} Wheather the states are deeply equal.
+ */
+function isDropdownsStateEqual(prevState, newState) {
+  return (
+    prevState.isOpen === newState.isOpen &&
+    prevState.inputValue === newState.inputValue &&
+    prevState.highlightedIndex === newState.highlightedIndex &&
+    prevState.selectedItem === newState.selectedItem
+  )
+}
+
 // Shared between all exports.
 const commonPropTypes = {
   environment: PropTypes.shape({
@@ -646,6 +676,7 @@ export {
   getItemAndIndex,
   useElementIds,
   getChangesOnSelection,
+  isDropdownsStateEqual,
   commonDropdownPropTypes,
   commonPropTypes,
 }