From 9e1728038976686f679e4bf867c8150a66d14293 Mon Sep 17 00:00:00 2001
From: Alexander Kurganov <me@akurganow.ru>
Date: Sat, 3 Oct 2020 17:44:55 +0300
Subject: [PATCH] feat: Support SSR. Closes #196

---
 __tests__/create-persisted-state.test.tsx | 28 +++++++++++++--
 src/utils/create-web-storage.ts           | 44 +++++++++++++----------
 src/utils/get-persisted-value.ts          |  2 +-
 3 files changed, 52 insertions(+), 22 deletions(-)

diff --git a/__tests__/create-persisted-state.test.tsx b/__tests__/create-persisted-state.test.tsx
index 44c68400..985d4bcd 100644
--- a/__tests__/create-persisted-state.test.tsx
+++ b/__tests__/create-persisted-state.test.tsx
@@ -1,10 +1,11 @@
 import { createPersistedState } from '../src'
 import storage from '../src/storages/local-storage'
+import createStorage from '../src/utils/create-web-storage'
 import { renderHook, cleanup, act } from '@testing-library/react-hooks'
 
-const [usePersistedState, clear] = createPersistedState('test', storage)
-
 describe('hook defined correctly', () => {
+  const [usePersistedState, clear] = createPersistedState('test', storage)
+
   beforeEach(() => {
     cleanup()
     clear()
@@ -32,3 +33,26 @@ describe('hook defined correctly', () => {
     expect(localStorage.__STORE__['persisted_state_hook:test']).toEqual(expected)
   })
 })
+
+describe('hook works on SSR', () => {
+  const testingSSRStorage = createStorage(undefined as unknown as Storage)
+  const [usePersistedState, clear] = createPersistedState('test', testingSSRStorage)
+
+  it('is callable', () => {
+    const { result } = renderHook(() => usePersistedState('foo', 'bar'))
+
+    expect(usePersistedState).toBeDefined()
+    expect(clear).toBeDefined()
+    expect(result.current).toBeDefined()
+  })
+
+  it('localstorage called correctly', () => {
+    const { result } = renderHook(() => usePersistedState('foo', 'bar'))
+
+    act(() => {
+      result.current[1]('baz')
+    })
+
+    expect(result.current[0]).toBe('baz')
+  })
+})
diff --git a/src/utils/create-web-storage.ts b/src/utils/create-web-storage.ts
index 311b19a2..3cc9badf 100644
--- a/src/utils/create-web-storage.ts
+++ b/src/utils/create-web-storage.ts
@@ -39,12 +39,12 @@ export default (storage: globalThis.Storage): Storage => ({
 
     if (Array.isArray(keys)) {
       keys.forEach(key => {
-        const item = storage.getItem(key)
+        const item = typeof storage !== 'undefined' ? storage.getItem(key) : undefined
 
         if (item) result[key] = item
       })
     } else {
-      const item = storage.getItem(keys)
+      const item = typeof storage !== 'undefined' ? storage.getItem(keys) : undefined
 
       if (item) result[keys] = item
     }
@@ -55,44 +55,50 @@ export default (storage: globalThis.Storage): Storage => ({
     const changes: { [key: string]: StorageChange } = {}
 
     Object.entries(items).forEach(([key, value]) => {
-      const oldValue = storage.getItem(key)
+      const oldValue = typeof storage !== 'undefined' ? storage.getItem(key) : undefined
 
-      storage.setItem(key, value)
+      if (typeof storage !== 'undefined') {
+        storage.setItem(key, value)
 
-      changes[key] = {
-        oldValue,
-        newValue: value,
+        changes[key] = {
+          oldValue,
+          newValue: value,
+        }
       }
     })
 
-    fireStorageEvent(changes)
+    if (Object.keys(changes).length > 0) fireStorageEvent(changes)
   },
   remove: keys => {
     const changes: { [key: string]: StorageChange } = {}
 
     if (Array.isArray(keys)) {
       keys.forEach(key => {
-        const oldValue = storage.getItem(key)
+        const oldValue = typeof storage !== 'undefined' ? storage.getItem(key) : undefined
 
-        storage.removeItem(key)
+        if (typeof storage !== 'undefined') {
+          storage.removeItem(key)
 
-        changes[key] = {
-          oldValue,
-          newValue: null,
+          changes[key] = {
+            oldValue,
+            newValue: null,
+          }
         }
       })
     } else {
-      const oldValue = storage.getItem(keys)
+      const oldValue = typeof storage !== 'undefined' ? storage.getItem(keys) : undefined
 
-      storage.removeItem(keys)
+      if (typeof storage !== 'undefined') {
+        storage.removeItem(keys)
 
-      changes[keys] = {
-        oldValue,
-        newValue: null,
+        changes[keys] = {
+          oldValue,
+          newValue: null,
+        }
       }
     }
 
-    fireStorageEvent(changes)
+    if (Object.keys(changes).length > 0) fireStorageEvent(changes)
   },
   onChanged,
 })
diff --git a/src/utils/get-persisted-value.ts b/src/utils/get-persisted-value.ts
index a89c9c3d..a64901de 100644
--- a/src/utils/get-persisted-value.ts
+++ b/src/utils/get-persisted-value.ts
@@ -1,6 +1,6 @@
 import isFunction from './is-function'
 
-export default function<T>(key:string, initialValue: T | (() => T), persist: string): T {
+export default function<T>(key:string, initialValue: T | (() => T), persist?: string): T {
   let initialPersist: { [x: string]: unknown }
 
   try {