1 files changed, 76 insertions, 0 deletions
diff --git a/src/lib/persisted_state.js b/src/lib/persisted_state.js
new file mode 100644
index 00000000..de1e5383
--- /dev/null
+++ b/src/lib/persisted_state.js
@@ -0,0 +1,76 @@
+import merge from 'lodash.merge'
+import objectPath from 'object-path'
+import { throttle } from 'lodash'
+import { inflate, deflate } from 'pako'
+
+const defaultReducer = (state, paths) => (
+  paths.length === 0 ? state : paths.reduce((substate, path) => {
+    objectPath.set(substate, path, objectPath.get(state, path))
+    return substate
+  }, {})
+)
+
+const defaultStorage = (() => {
+  const hasLocalStorage = typeof window !== 'undefined' && window.localStorage
+  if (hasLocalStorage) {
+    return window.localStorage
+  }
+
+  class InternalStorage {
+    setItem (key, item) {
+      this[key] = item
+      return item
+    }
+    getItem (key) {
+      return this[key]
+    }
+    removeItem (key) {
+      delete this[key]
+    }
+    clear () {
+      Object.keys(this).forEach(key => delete this[key])
+    }
+  }
+
+  return new InternalStorage()
+})()
+
+const defaultSetState = (key, state, storage) => {
+  return storage.setItem(key, deflate(JSON.stringify(state), { to: 'string' }))
+}
+
+export default function createPersistedState ({
+  key = 'vuex',
+  paths = [],
+  getState = (key, storage) => {
+    let value = storage.getItem(key)
+    try {
+      value = inflate(value, { to: 'string' })
+    } catch (e) {
+      console.log("Couldn't inflate value... Maybe upgrading")
+    }
+    return value && value !== 'undefined' ? JSON.parse(value) : undefined
+  },
+  setState = throttle(defaultSetState, 5000),
+  reducer = defaultReducer,
+  storage = defaultStorage,
+  subscriber = store => handler => store.subscribe(handler)
+} = {}) {
+  return store => {
+    const savedState = getState(key, storage)
+    if (typeof savedState === 'object') {
+      store.replaceState(
+        merge({}, store.state, savedState)
+      )
+    }
+
+    subscriber(store)((mutation, state) => {
+      try {
+        setState(key, reducer(state, paths), storage)
+      } catch (e) {
+        console.log("Couldn't persist state:")
+        console.log(e)
+      }
+    })
+  }
+}