(persist): Add option to opt-out of serializing and deserializing sta…

…te from storage (#507)

* Add serializer key to PersistConfiog to opt-in serializing input & output from storage

* (docs): Add serialize key to PersistConfig

docs/api.md

@@ -60,6 +60,7 @@ The Persistor is a redux store unto itself, plus
   keyPrefix?: string, // will be prefixed to the storage key
   debug?: boolean, // true -> verbose logs
   stateReconciler?: false | StateReconciler, // false -> do not automatically reconcile state
+  serialize?: boolean, // false -> do not call JSON.parse & stringify when setting & getting from storage
 }
 ```
 
@@ -93,7 +94,7 @@ Where Persistoid is [defined below](#type-persistoid).
 
 ### `type Persistoid`
 ```js
-{ 
+{
   update: (State) => void
 }
 ```
@@ -118,4 +119,4 @@ A function which reconciles:
 - **inboundState**: the state being rehydrated from storage
 - **originalState**: the state before the REHYDRATE action
 - **reducedState**: the store state *after* the REHYDRATE action but *before* the reconcilliation
-into final "rehydrated" state.
+into final "rehydrated" state.

src/createPersistoid.js

@@ -13,8 +13,8 @@ export default function createPersistoid(config: PersistConfig): Persistoid {
   const storageKey = `${config.keyPrefix !== undefined
     ? config.keyPrefix
     : KEY_PREFIX}${config.key}`
-
   const storage = config.storage
+  const serialize = config.serialize === false ? x => x : defaultSerialize
 
   // initialize stateful values
   let lastState = {}
@@ -106,6 +106,6 @@ export default function createPersistoid(config: PersistConfig): Persistoid {
 }
 
 // @NOTE in the future this may be exposed via config
-function serialize(data) {
+function defaultSerialize(data) {
   return JSON.stringify(data)
 }

src/getStoredState.js

@@ -13,7 +13,7 @@ export default function getStoredState(
     : KEY_PREFIX}${config.key}`
   const storage = config.storage
   const debug = config.debug
-
+  const deserialize = config.serialize === false ? x => x : defaultDeserialize
   return storage.getItem(storageKey).then(serialized => {
     if (!serialized) return undefined
     else {
@@ -38,6 +38,6 @@ export default function getStoredState(
   })
 }
 
-function deserialize(serial) {
+function defaultDeserialize(serial) {
   return JSON.parse(serial)
 }

src/types.js

@@ -22,6 +22,7 @@ export type PersistConfig = {
   stateReconciler?: false | Function,
   getStoredState?: PersistConfig => Promise<PersistedState>, // used for migrations
   debug?: boolean,
+  serialize?: boolean,
 }
 
 export type PersistorOptions = {