From c3fabac0d17d500bfa8ebd4938f2ee7be216cd1b Mon Sep 17 00:00:00 2001
From: chornos13 <chornos13@hotmail.com>
Date: Thu, 18 Feb 2021 12:02:55 +0700
Subject: [PATCH] feat(hooks): add hook usePersistedState

---
 .../__test__/usePersistedState.test.tsx       | 96 +++++++++++++++++++
 .../usePersistedState/usePersistedState.tsx   | 28 ++++++
 2 files changed, 124 insertions(+)
 create mode 100644 src/hooks/usePersistedState/__test__/usePersistedState.test.tsx
 create mode 100644 src/hooks/usePersistedState/usePersistedState.tsx

diff --git a/src/hooks/usePersistedState/__test__/usePersistedState.test.tsx b/src/hooks/usePersistedState/__test__/usePersistedState.test.tsx
new file mode 100644
index 0000000..9b747d6
--- /dev/null
+++ b/src/hooks/usePersistedState/__test__/usePersistedState.test.tsx
@@ -0,0 +1,96 @@
+import { renderHook, act } from '@testing-library/react-hooks'
+import usePersistedState from 'hooks/usePersistedState/usePersistedState'
+
+const mockGetItem = jest.fn()
+const mockSetItem = jest.fn()
+Storage.prototype.getItem = mockGetItem
+Storage.prototype.setItem = mockSetItem
+
+describe('basic function persisted state', () => {
+  afterEach(() => {
+    mockGetItem.mockReset()
+    mockSetItem.mockReset()
+  })
+
+  test('should return defaultValue if no saved data', () => {
+    // arrange
+    mockGetItem.mockReturnValue(null)
+    const defaultValue = 'anyDefaultValue'
+    const { result } = renderHook(() =>
+      usePersistedState('anyKey', defaultValue),
+    )
+
+    const [value] = result.current
+    expect(value).toEqual(defaultValue)
+  })
+
+  test('should return stored value for that key if key hook changed', () => {
+    // arrange
+    mockGetItem.mockImplementation((key) => {
+      return {
+        anyInitialKey: 'anyValueInitialKey',
+        anyChangedKey: 'anyValueChangedKey',
+      }[key]
+    })
+    const { result, rerender } = renderHook(
+      (isNewKey) =>
+        usePersistedState(
+          isNewKey ? 'anyChangedKey' : 'anyInitialKey',
+          'anyDefaultValue',
+        ),
+      {
+        initialProps: false,
+      },
+    )
+    expect(result.current[0]).toEqual('anyValueInitialKey')
+
+    // act
+    rerender(true)
+
+    // assert
+    expect(result.current[0]).toEqual('anyValueChangedKey')
+  })
+
+  test('should parsing JSON savedData from stored value', () => {
+    // arrange
+    const jsonData = JSON.stringify('anyJSONData')
+    mockGetItem.mockReturnValue(jsonData)
+    const { result } = renderHook(() =>
+      usePersistedState('anyKey', 'anyDefaultValue'),
+    )
+
+    const [value] = result.current
+    expect(value).toEqual(JSON.parse(jsonData))
+  })
+
+  test('should return stored value if failed parsing to JSON', () => {
+    // arrange
+    const invalidJSONData = 'anyInvalidJSONData'
+    mockGetItem.mockReturnValue(invalidJSONData)
+    const { result } = renderHook(() =>
+      usePersistedState('anyKey', 'anyDefaultValue'),
+    )
+
+    const [value] = result.current
+    expect(value).toEqual(invalidJSONData)
+  })
+
+  test('should saved data to localStorage when call setValue', () => {
+    // arrange
+    const savedData = 'anyStoreData'
+    const { result } = renderHook(() =>
+      usePersistedState('anyKey', 'anyDefaultValue'),
+    )
+    mockSetItem.mockImplementation((key, value) => {
+      mockGetItem.mockReturnValue(value)
+    })
+
+    // act
+    const [, setValue] = result.current
+    act(() => setValue(savedData))
+
+    expect(mockGetItem.getMockImplementation()()).toEqual(
+      JSON.stringify(savedData),
+    )
+  })
+})
diff --git a/src/hooks/usePersistedState/usePersistedState.tsx b/src/hooks/usePersistedState/usePersistedState.tsx
new file mode 100644
index 0000000..4698a68
--- /dev/null
+++ b/src/hooks/usePersistedState/usePersistedState.tsx
@@ -0,0 +1,28 @@
+import { useEffect, useState } from 'react'
+
+function usePersistedState<T = any>(key: string, defaultValue: any) {
+  const [isLoading, setIsLoading] = useState(true)
+  const [value, setValue] = useState<T>(defaultValue)
+
+  useEffect(() => {
+    const persistedValue = localStorage.getItem(key)
+    if (![null, undefined].includes(persistedValue)) {
+      let savedValue
+      try {
+        savedValue = JSON.parse(persistedValue)
+      } catch (e) {
+        savedValue = persistedValue
+      }
+      setValue(savedValue)
+    }
+    setIsLoading(false)
+  }, [key])
+
+  useEffect(() => {
+    localStorage.setItem(key, JSON.stringify(value))
+  }, [key, value])
+
+  return [value, setValue, isLoading] as const
+}
+
+export default usePersistedState