mongez-cache-session-storage

name

mongez-cache-session-storage

description

Reference for `PlainSessionStorageDriver` — tab-scoped `window.sessionStorage` backend with the same envelope, TTL, prefix, and corruption-recovery semantics as the localStorage driver; data survives refresh but not tab close. TRIGGER when: code calls `new PlainSessionStorageDriver()` or imports `PlainSessionStorageDriver` from `@mongez/cache`; user asks "how do I cache scroll position / draft form data per tab", "how do I make a wizard remember progress through refreshes only", or "how do I use sessionStorage with `@mongez/cache`"; `import { PlainSessionStorageDriver } from "@mongez/cache"`. SKIP: cross-session persistence — use `mongez-cache-local-storage`; in-memory only cache — use `mongez-cache-runtime`; encrypted variant of session storage — use `mongez-cache-encryption` or `mongez-cache-encrypted-cache`; choosing among all drivers — use `mongez-cache-drivers`.

PlainSessionStorageDriver

The session-storage variant of the plain driver. Same contract, same envelope, same TTL — but backed by window.sessionStorage instead of localStorage. Values disappear when the tab closes.

Signature

import { PlainSessionStorageDriver } from "@mongez/cache";

class PlainSessionStorageDriver extends BaseCacheEngine implements CacheDriverInterface {
  public storage: Storage;          // = sessionStorage
}

When to use it

• Tab-scoped state: scroll position, draft form data, multi-step wizard progress.
• Auth tokens you want gone on tab close — though encrypted localStorage with a short TTL is usually the better trade-off.
• Shopping cart for an unauthenticated user — sessionStorage lets the cart survive a refresh but not a tab close.

For state that should outlive the tab, use PlainLocalStorageDriver instead. For state that should only live for the current page-view, use RunTimeDriver.

Usage

import { PlainSessionStorageDriver, setCacheConfigurations } from "@mongez/cache";

setCacheConfigurations({
  driver: new PlainSessionStorageDriver(),
});

cache.set("scroll.y", 312);
cache.set("draft", { title: "", body: "Half-written..." });

cache.get("scroll.y");              // 312

Everything in local-storage.md applies — the envelope format, TTL behavior, corruption recovery, prefix handling, and SSR caveats are identical. Only the backing storage differs.

Gotchas

• Tabs are isolated. Two tabs of the same site each have their own sessionStorage. Two tabs of the same localStorage share data; two tabs of the same sessionStorage don't.
• clear() is not prefix-scoped. Same as the local-storage driver — wipes the entire session storage backend for the origin.
• sessionStorage also has a ~5MB cap. Same quota behavior as localStorage.