> ## Documentation Index
> Fetch the complete documentation index at: https://brushysuite.gfrancodev.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Node vs browser

> Runtime differences, SSR, and instance registry.

`@brushy/storage` is isomorphic: one API for Node.js, browsers, React Native, and SSR.

## Runtime matrix

| Feature                | Node.js   | Browser | SSR (no storage) |
| ---------------------- | --------- | ------- | ---------------- |
| In-memory cache        | ✅         | ✅       | ✅                |
| `persist: "local"`     | ❌ (no-op) | ✅       | ❌                |
| `persist: "session"`   | ❌ (no-op) | ✅       | ❌                |
| `BroadcastChannel` bus | ❌         | ✅       | ❌                |
| Registry bus           | ✅         | ✅       | ✅                |
| Expiry timer `unref()` | ✅         | N/A     | ✅                |

## SSR with React

`@brushy/storage-react` uses `getServerSnapshot` to return the `initialValue` on the server, avoiding hydration mismatches:

```tsx theme={null}
const { value } = useStorage("theme", "light");
// Server: always "light"
// Client: reads from storage after hydration
```

Create the storage instance once per app (singleton `id`) and pass it to `StorageProvider`.

## Instance registry

* `createStorage({ id })` returns a shared instance per process for the same `id`
* `getStorageInstance(id)` retrieves without creating
* `close()` removes from registry; next `createStorage` creates fresh

## Node.js timers

The expiry `checkperiod` interval calls `unref()` when available so background scans do not block process exit.

## Cloning

`useClones: true` uses `structuredClone` when available. In older environments it falls back to JSON round-trip (functions and `undefined` in objects are lost).

## DI integration

Register storage as a singleton in your DI container:

```typescript theme={null}
import { createStorage } from "@brushy/storage";
import { createToken, defineModule } from "@brushy/di-core";

export const APP_CACHE = createToken("APP_CACHE");

export const cacheModule = defineModule({
  cache: {
    useFactory: () =>
      createStorage({
        id: "my-app",
        prefix: "@myapp:",
        persist: "local",
      }),
    lifecycle: "singleton",
  },
});
```

See [Examples](/examples/overview) for Vite, Expo, Express, and Fastify layouts.