addon API for storing state per-session or per-app.

Issue: we removed the use of URL params for storing state. This will be an issue if apps reload (e.g. because HMR isn’t working right, see for instance https://github.com/storybooks/storybook/issues/5267).

Right now we have an adhoc way of using session/localStorage for storing things. We also have retained setQueryParams but it no longer actually affects the URL so will not survive reloads etc.

We should resolve this for v5.

[leoyli]

@shilman, this is not working in the beta.1 version. (not sure about the prior versions)

For example, in a decorator I call api.setQueryParams({ test: 'abc' }). The URL is not changed and the subsequent call both (console.dir(api.getUrlState()) and console.dir(api.getQueryParam())) was not showing the query parameter I provided…

Any clue or should I open a new issue?!

[tmeasday]

Here’s what I sketched out in my head:

What if we update setState to have the signature:

function setState(update: object, persistence: 'none' | 'session' | 'forever') {}

When we setState, we may also save a “subset” of the state into sessionStorage and localStorage based on the above.

When we initialize the state, we will combine:

1. The default initial state returned by each module
2. The forever state
3. The session state

Merging them with preference in that order (i.e. session > forever > defaults)