persist user preferences through localStorage

src/components/molecules/FormFields/Price/index.tsx

@@ -6,6 +6,7 @@ import Tabs from '../../../atoms/Tabs'
 import Fixed from './Fixed'
 import Dynamic from './Dynamic'
 import { useField } from 'formik'
+import { useUserPreferences } from '../../../../providers/UserPreferences'
 
 const query = graphql`
   query PriceFieldQuery {
@@ -35,6 +36,7 @@ const query = graphql`
 `
 
 export default function Price(props: InputProps): ReactElement {
+  const { debug } = useUserPreferences()
   const data = useStaticQuery(query)
   const content = data.content.edges[0].node.childPagesJson.price
 
@@ -89,9 +91,11 @@ export default function Price(props: InputProps): ReactElement {
   return (
     <div className={styles.price}>
       <Tabs items={tabs} handleTabChange={handleTabChange} />
+      {debug === true && (
         <pre>
           <code>{JSON.stringify(field.value)}</code>
         </pre>
+      )}
     </div>
   )
 }

src/providers/UserPreferences.tsx

@@ -3,7 +3,8 @@ import React, {
   useContext,
   ReactElement,
   ReactNode,
-  useState
+  useState,
+  useEffect
 } from 'react'
 
 declare type Currency = 'EUR' | 'USD'
@@ -11,19 +12,46 @@ declare type Currency = 'EUR' | 'USD'
 interface UserPreferencesValue {
   debug: boolean
   currency: Currency
-  setDebug: (value: boolean) => void
-  setCurrency: (value: string) => void
+  setDebug?: (value: boolean) => void
+  setCurrency?: (value: string) => void
 }
 
 const UserPreferencesContext = createContext(null)
 
+const localStorageKey = 'ocean-user-preferences'
+
+function getLocalStorage() {
+  const storageParsed =
+    window && JSON.parse(window.localStorage.getItem(localStorageKey))
+  return storageParsed
+}
+
+function setLocalStorage(values: UserPreferencesValue) {
+  return (
+    window &&
+    window.localStorage.setItem(localStorageKey, JSON.stringify(values))
+  )
+}
+
 function UserPreferencesProvider({
   children
 }: {
   children: ReactNode
 }): ReactElement {
-  const [debug, setDebug] = useState<boolean>(false)
-  const [currency, setCurrency] = useState<Currency>('EUR')
+  const localStorage = getLocalStorage()
+
+  // Set default values from localStorage
+  const [debug, setDebug] = useState<boolean>(
+    (localStorage && localStorage.debug) || false
+  )
+  const [currency, setCurrency] = useState<Currency>(
+    (localStorage && localStorage.currency) || 'EUR'
+  )
+
+  // Write values to localStorage on change
+  useEffect(() => {
+    setLocalStorage({ debug, currency })
+  }, [debug, currency])
 
   return (
     <UserPreferencesContext.Provider