From 1bc1e49d85e60d1ccf36c80df65f0fcbc7d1e3ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20H=C3=B8egh?= <tobias@tujo.no>
Date: Fri, 13 Dec 2024 14:14:01 +0100
Subject: [PATCH] Add `useWeakSharedState`

---
 .../helpers/__tests__/useSharedState.test.ts  | 75 +++++++++++++------
 .../src/shared/helpers/useSharedState.tsx     |  7 +-
 2 files changed, 56 insertions(+), 26 deletions(-)

diff --git a/packages/dnb-eufemia/src/shared/helpers/__tests__/useSharedState.test.ts b/packages/dnb-eufemia/src/shared/helpers/__tests__/useSharedState.test.ts
index aef19b89884..07a1bced90e 100644
--- a/packages/dnb-eufemia/src/shared/helpers/__tests__/useSharedState.test.ts
+++ b/packages/dnb-eufemia/src/shared/helpers/__tests__/useSharedState.test.ts
@@ -5,6 +5,7 @@ import {
   createSharedState,
   SharedStateId,
   createReferenceKey,
+  useWeakSharedState,
 } from '../useSharedState'
 import { createContext } from 'react'
 
@@ -110,30 +111,6 @@ describe('useSharedState', () => {
     expect(result.current.data).toEqual({ test: 'initial' })
   })
 
-  it('should delete the shared state when all components have been unmounted', () => {
-    const identifier = {}
-
-    const { unmount: unmountA } = renderHook(() =>
-      useSharedState(identifier, { test: 'initial' })
-    )
-    const { unmount: unmountB } = renderHook(() =>
-      useSharedState(identifier)
-    )
-
-    const getStateOf = (identifier) => {
-      return createSharedState(identifier).get()
-    }
-
-    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
-    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
-
-    unmountA()
-    unmountB()
-
-    expect(getStateOf(identifier)).toEqual(undefined)
-    expect(getStateOf(identifier)).toEqual(undefined)
-  })
-
   it('should return undefined data when no ID is given', () => {
     const { result } = renderHook(() =>
       useSharedState(null, { test: 'initial' })
@@ -276,6 +253,56 @@ describe('useSharedState', () => {
   })
 })
 
+describe('useWeakSharedState', () => {
+  it('should delete the shared state when all components have been unmounted', () => {
+    const identifier = {}
+
+    const { unmount: unmountA } = renderHook(() =>
+      useWeakSharedState(identifier, { test: 'initial' })
+    )
+    const { unmount: unmountB } = renderHook(() =>
+      useWeakSharedState(identifier)
+    )
+
+    const getStateOf = (identifier) => {
+      return createSharedState(identifier).get()
+    }
+
+    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
+    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
+
+    unmountA()
+    unmountB()
+
+    expect(getStateOf(identifier)).toEqual(undefined)
+    expect(getStateOf(identifier)).toEqual(undefined)
+  })
+
+  it('when not using weak, should not delete the shared state when all components have been unmounted', () => {
+    const identifier = {}
+
+    const { unmount: unmountA } = renderHook(() =>
+      useSharedState(identifier, { test: 'initial' })
+    )
+    const { unmount: unmountB } = renderHook(() =>
+      useSharedState(identifier)
+    )
+
+    const getStateOf = (identifier) => {
+      return createSharedState(identifier).get()
+    }
+
+    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
+    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
+
+    unmountA()
+    unmountB()
+
+    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
+    expect(getStateOf(identifier)).toEqual({ test: 'initial' })
+  })
+})
+
 describe('createReferenceKey', () => {
   it('should return the same object for the same references', () => {
     const ref1 = {}
diff --git a/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx b/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx
index 5a8457f4fcf..3ae031e51de 100644
--- a/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx
+++ b/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx
@@ -20,7 +20,7 @@ export type SharedStateId =
   | Record<string, unknown>
 
 /**
- * Custom hook that provides shared state functionality.
+ * The shared state will be deleted when all components have been unmounted.
  */
 export function useWeakSharedState<
   Data,
@@ -45,7 +45,10 @@ export function useSharedState<Data>(
   /** Optional callback function to be called when the shared state is set from another instance/component. */
   onChange = null,
   /** Optional configuration options. */
-  { weak = false } = {}
+  {
+    /** When set to `true`, the shared state will be deleted when all components have been unmounted. */
+    weak = false,
+  } = {}
 ) {
   const [, forceUpdate] = useReducer(() => ({}), {})
   const hasMountedRef = useMounted()