feature/setup-state-persistence

app/index.js

@@ -1,5 +1,7 @@
 import React, { Component } from 'react'
 import { Provider } from 'react-redux'
+import { init } from '@state/actions/app'
+import { apiInit } from '@state/actions/api'
 import store from '@state/store'
 import OnboardingStackNavigation from '@navigation/onboarding-stack'
 import { setTopLevelNavigator } from '@state/middlewares/navigation/navigation'
@@ -13,5 +15,10 @@ export default class App extends Component {
     )
   }
 
+  componentDidMount() {
+    store.dispatch(init())
+    store.dispatch(apiInit())
+  }
+
   goToNextScreen = () => console.log('goToNextScreen')
 }

app/persistence-api/__tests__/persistence-api.test.js

@@ -0,0 +1,127 @@
+// import PersistenceApi from '@persistence-api/persistence-api'
+
+describe('persistence-api', () => {
+  describe('getState', () => {
+    describe('state exists in storage', () => {
+      let PersistenceApi
+      beforeEach(() => {
+        jest.resetAllMocks()
+        jest.mock('react-native', () => ({
+          AsyncStorage: {
+            getItem: jest.fn(() =>
+              new Promise(resolve =>
+                resolve('{"mockedData": "mockedData"}')
+              )
+            ),
+            setItem: jest.fn()
+          }
+        }))
+        PersistenceApi = require('@persistence-api/persistence-api').default
+      })
+
+      it('should return state from storage', async () => {
+        const state = await PersistenceApi.getState()
+
+        expect(state).toEqual({
+          mockedData: 'mockedData'
+        })
+      })
+    })
+
+    describe('state does not exist in storage', () => {
+      let PersistenceApi
+      beforeEach(() => {
+        jest.resetAllMocks()
+        jest.doMock('react-native', () => ({
+          AsyncStorage: {
+            getItem: jest.fn(() => {
+              return new Promise(resolve =>
+                resolve('{}')
+              )
+            }),
+            setItem: jest.fn()
+          }
+        }))
+        PersistenceApi = require('@persistence-api/persistence-api').default
+      })
+
+      it('should return `undefined`', async () => {
+        const state = await PersistenceApi.getState()
+
+        expect(state).toEqual(undefined)
+      })
+    })
+  })
+
+  describe('saveState', () => {
+    let PersistenceApi, AsyncStorage, state
+    beforeEach(() => {
+      jest.resetAllMocks()
+      jest.mock('react-native', () => ({
+        AsyncStorage: {
+          getItem: jest.fn(),
+          setItem: jest.fn((key, state) =>
+            new Promise(resolve =>
+              resolve(undefined)
+            )
+          )
+        }
+      }))
+      PersistenceApi = require('@persistence-api/persistence-api').default
+      AsyncStorage = require('react-native').AsyncStorage
+    })
+
+    describe('state is serializable', () => {
+      beforeEach(() => {
+        state = {
+          someState: 'some state'
+        }
+      })
+
+      it('should save state as string', async () => {
+        await PersistenceApi.saveState(state)
+
+        expect(AsyncStorage.setItem).toHaveBeenCalledWith('STORAGE:STATE', '{\"someState\":\"some state\"}')
+      })
+    })
+
+    describe('state is not serializable', () => {
+      let state
+      beforeEach(() => {
+        state = {};
+        state.myself = state;
+      })
+
+      it('should throw error', async done => {
+        try {
+          await PersistenceApi.saveState(state)
+          fail()
+        }
+        catch (err) {
+          done()
+        }
+      })
+    })
+
+    describe('Storage fails to save', () => {
+      let state
+      beforeEach(() => {
+        AsyncStorage.setItem = jest.fn(() => 
+          new Promise((_, reject) => 
+            reject()
+          )
+        )
+      })
+
+      it('should throw error', async done => {
+        try {
+          await PersistenceApi.saveState(state)
+          fail()
+        }
+        catch (err) {
+          done()
+        }
+      })
+    })
+  })
+})

app/persistence-api/index.js

@@ -0,0 +1,3 @@
+import persistenceApi from './persistence-api'
+
+export default persistenceApi

app/persistence-api/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "@persistence-api"
+}

app/persistence-api/persistence-api.js

@@ -0,0 +1,20 @@
+import { AsyncStorage } from 'react-native'
+
+const STORAGE_KEY_STATE = 'STORAGE:STATE'
+
+export default class PersistenceApi {
+  static getState = async () => {
+    const result = await AsyncStorage.getItem(STORAGE_KEY_STATE)
+    try {
+      return JSON.parse(result)
+    }
+    catch (_) {
+      return undefined
+    }
+  }
+
+  static saveState = async (state) => {
+    const stateString = JSON.stringify(state)
+    await AsyncStorage.setItem(STORAGE_KEY_STATE, stateString)
+  }
+}

app/state/actions/app.js

@@ -0,0 +1,8 @@
+export const INIT = 'INIT'
+
+export const init = () => {
+  return {
+    type: INIT,
+    payload: {}
+  }
+}

app/state/actions/persistence.js

@@ -0,0 +1,57 @@
+export const PERSISTENCE_LOAD_STATE_REQUEST = 'PERSISTENCE:LOAD_STATE_REQUEST'
+export const PERSISTENCE_LOAD_STATE_SUCCESS = 'PERSISTENCE:LOAD_STATE_SUCCESS'
+export const PERSISTENCE_LOAD_STATE_FAILURE = 'PERSISTENCE:LOAD_STATE_FAILURE'
+
+export const PERSISTENCE_SAVE_STATE_REQUEST = 'PERSISTENCE:SAVE_STATE_REQUEST'
+export const PERSISTENCE_SAVE_STATE_SUCCESS = 'PERSISTENCE:SAVE_STATE_SUCCESS'
+export const PERSISTENCE_SAVE_STATE_FAILURE = 'PERSISTENCE:SAVE_STATE_FAILURE'
+
+export const loadStateRequest = () => {
+  return {
+    type: PERSISTENCE_LOAD_STATE_REQUEST,
+    payload: {}
+  }
+}
+
+export const loadStateSuccess = (state) => {
+  return {
+    type: PERSISTENCE_LOAD_STATE_SUCCESS,
+    payload: {
+      state
+    }
+  }
+}
+
+export const loadStateFailure = (error) => {
+  return {
+    type: PERSISTENCE_LOAD_STATE_FAILURE,
+    payload: {
+      error
+    }
+  }
+}
+
+export const saveStateRequest = (state) => {
+  return {
+    type: PERSISTENCE_SAVE_STATE_REQUEST,
+    payload: {
+      state
+    }
+  }
+}
+
+export const saveStateSuccess = () => {
+  return {
+    type: PERSISTENCE_SAVE_STATE_SUCCESS,
+    payload: {}
+  }
+}
+
+export const saveStateFailure = (error) => {
+  return {
+    type: PERSISTENCE_SAVE_STATE_FAILURE,
+    payload: {
+      error
+    }
+  }
+}

app/state/middlewares/logger/index.js

@@ -0,0 +1,7 @@
+export default store => next => action => {
+  console.log('prevState', store.getState())
+  console.log('action', action)
+  const nextAction = next(action)
+  console.log('nextState', store.getState())
+  return nextAction
+}