Restoring cached data

At the beginning of the chapter, when implementing the updateUser method in UserService, we cached the user object in case of any errors that may wipe out user-provided data:

src/app/user/user/user.service.ts
updateUser(id: string, user: IUser): Observable<IUser> {
  ...
  This.cache.setItem('draft-user', user)
  ...
}

Consider a scenario where the user may be temporarily offline when they attempt to save their data. In this case, our updateUser function will save the data.

Let’s see how we can restore this data in ProfileComponent when loading the user profile:

1. Start by adding functions named loadFromCache and clearCache to the ProfileComponent class:

   src/app/user/profile.component.ts
   private loadFromCache(): Observable<User | null> {
     let user = null
     try {
       const draftUser = this.cache.getItem('draft-user')
       if (draftUser != null) {
         user = User.Build(JSON.parse(draftUser)...