persist-unavailable

[wizzard] The wizard cannot be saved. this browser did not allow localStorage, which private
windows commonly do. pass a storage of your own, or accept that this session will not survive a reload.
…/errors/persist-unavailable
[wizzard] The saved wizard could not be read. storage refused the read (<error>). pass a storage
of your own, or accept that this session starts fresh. …/errors/persist-unavailable

A warning from persist() in @wizzard-packages/plugins/persist, printed with console.warn once for the life of the plugin. The wizard keeps working in memory; only the saving stops.

The first form fires when the browser storage storage names - 'local', the default, or 'session' - cannot be had: none exists, as during server rendering, or it throws when it is touched. Private windows do that on the property rather than on a call, which is why merely reading globalThis.sessionStorage counts, and why the plugin reads it rather than your code. The message names the one it asked for (localStorage or sessionStorage). Asking for 'session' never falls back to localStorage: a store chosen because it dies with the tab is not replaced by one that outlives it. The second form fires when a storage exists but getItem throws: a browser that admits the object and then refuses to use it.

In both cases onRestore receives { restored: false, reason: 'persist/unavailable' }, so the host can say that this session will not come back rather than leaving an empty form after a reload to look like a bug.

The fix is a storage the environment allows. 'session' is sometimes allowed where 'local' is not, and anything with synchronous getItem and setItem works, including an object over a Map:

const memory = new Map<string, string>();

persist({
  key: 'signup',
  storage: {
    getItem: (key) => memory.get(key) ?? null,
    setItem: (key, value) => void memory.set(key, value),
  },
});