allow empty keyPrefix

Author: Zack Story

package.json

@@ -1,6 +1,6 @@
 {
   "name": "redux-persist",
-  "version": "4.0.0-alpha3",
+  "version": "4.0.0-alpha4",
   "description": "persist and rehydrate redux stores",
   "main": "lib/index.js",
   "scripts": {

src/createPersistor.js

@@ -12,7 +12,7 @@ export default function createPersistor (store, config) {
   const whitelist = config.whitelist || false
   const transforms = config.transforms || []
   const debounce = config.debounce || false
-  const keyPrefix = config.keyPrefix || KEY_PREFIX
+  const keyPrefix = config.keyPrefix !== undefined ? config.keyPrefix : KEY_PREFIX
 
   // pluggable state shape (e.g. immutablejs)
   const stateInit = config._stateInit || {}

src/getStoredState.js

@@ -8,7 +8,7 @@ export default function getStoredState (config, onComplete) {
   const blacklist = config.blacklist || []
   const whitelist = config.whitelist || false
   const transforms = config.transforms || []
-  const keyPrefix = config.keyPrefix || KEY_PREFIX
+  const keyPrefix = config.keyPrefix !== undefined ? config.keyPrefix : KEY_PREFIX
 
   // fallback getAllKeys to `keys` if present (LocalForage compatability)
   if (storage.keys && !storage.getAllKeys) storage = {...storage, getAllKeys: storage.keys}

src/purgeStoredState.js

@@ -2,7 +2,7 @@ import { KEY_PREFIX } from './constants'
 
 export default function purgeStoredState (config, keys) {
   const storage = config.storage
-  const keyPrefix = config.keyPrefix || KEY_PREFIX
+  const keyPrefix = config.keyPrefix !== undefined ? config.keyPrefix : KEY_PREFIX
 
   // basic validation
   if (Array.isArray(config)) throw new Error('redux-persist: purgeStoredState requires config as a first argument (found array). An array of keys is the optional second argument.')