feat: async migrations

docs/migrations.md

@@ -13,7 +13,8 @@ const migrations = {
  device: undefined 
  }
  },
- 1: (state) => {
+ // Async functions are allowed
+ 1: async (state) => {
  // migration to keep only device state
  return {
  device: state.device

src/createMigrate.ts

@@ -8,14 +8,14 @@ export default function createMigrate(
  config?: { debug: boolean }
 ): (state: PersistedState, currentVersion: number) => Promise<PersistedState> {
  const { debug } = config || {}
- return function(
+ return async function (
  state: PersistedState,
  currentVersion: number
  ): Promise<PersistedState> {
  if (!state) {
  if (process.env.NODE_ENV !== 'production' && debug)
  console.log('redux-persist: no inbound state, skipping migration')
- return Promise.resolve(undefined)
+ return undefined
  }
 
  const inboundVersion: number =
@@ -25,7 +25,7 @@ export default function createMigrate(
  if (inboundVersion === currentVersion) {
  if (process.env.NODE_ENV !== 'production' && debug)
  console.log('redux-persist: versions match, noop migration')
- return Promise.resolve(state)
+ return state
  }
  if (inboundVersion > currentVersion) {
  if (process.env.NODE_ENV !== 'production')
@@ -40,18 +40,17 @@ export default function createMigrate(
 
  if (process.env.NODE_ENV !== 'production' && debug)
  console.log('redux-persist: migrationKeys', migrationKeys)
- try {
- const migratedState: any = migrationKeys.reduce((state: any, versionKey) => {
- if (process.env.NODE_ENV !== 'production' && debug)
- console.log(
- 'redux-persist: running migration for versionKey',
- versionKey
- )
- return migrations[versionKey](state)
- }, state)
- return Promise.resolve(migratedState)
- } catch (err) {
- return Promise.reject(err)
+ let migratedState: any = state
+
+ for (const versionKey of migrationKeys) {
+ if (process.env.NODE_ENV !== 'production' && debug)
+ console.log(
+ 'redux-persist: running migration for versionKey',
+ versionKey
+ )
+ migratedState = await migrations[versionKey](migratedState)
  }
+
+ return migratedState
  }
 }

src/types.ts

@@ -84,7 +84,9 @@ export interface WebStorage extends Storage {
 }
 
 export interface MigrationManifest {
- [key: string]: (state: PersistedState) => PersistedState;
+ [key: string]:
+ | ((state: PersistedState) => PersistedState)
+ | ((state: PersistedState) => Promise<PersistedState>)
 }
 
 /**