'npm run serve' doesn't work, and looks like data is not persisted

[goodaleb-cloudbees]

on Ubuntu 16.04, after successfully running npm run build, when I run npm run serve, I get this:

Unable to read file: /users/home/<<myUsername>>/PersonalProjects/JournalBook/src/node_modules/idb/lib/idb.mjs

ReferenceError: IDBIndex is not defined
method: JkW7
at: /users/home/<<myUsername>>/PersonalProjects/JournalBook/src/node_modules/idb/lib/idb.mjs:87:0

It looks like is looking for node_modules inside src directory, but is actually in root of project.

[goodaleb-cloudbees]

By the way, npm run dev and npm start works just fine, so I guess this is no big deal, but since the command is mentioned in your docs, maybe the docs should at least be modified?

[goodaleb-cloudbees]

Well, actually....npm start launches the site, but if I shut it down and run npm start again, the entries are gone!. So, data is not retained or written to the filesystem anywhere for persistence? I don't know much about IDB, but why can't the data be written out between launches?
So, maybe I must further deploy this somewhere in a different configuration? Some help in the documentation would be useful regarding this. Obviously, if data cannot persist, this is useless to me.