chore(docs): add README

README.md

@@ -2,6 +2,74 @@
   - SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors
   - SPDX-License-Identifier: GPL-3.0-or-later
 -->
+
 # @nextcloud/browser-storage
 
+![GitHub package.json version](https://img.shields.io/github/package-json/v/nextcloud-libraries/nextcloud-browser-storage?style=flat) [![NPM Version](https://img.shields.io/npm/v/%40nextcloud%2Fbrowser-storage?style=flat)](https://npmjs.org/@nextcloud/browser-storage)
+[![BundleJS Size](https://deno.bundlejs.com/badge?q=@nextcloud/browser-storage&treeshake=%5B%7B+getBuilder+%7D%5D)](https://bundlejs.com/?q=%40nextcloud%2Fbrowser-storage%400.4.0&treeshake=%5B%7B+getBuilder+%7D%5D)
+[![License](https://img.shields.io/github/license/nextcloud-libraries/nextcloud-browser-storage)](https://github.com/nextcloud-libraries/nextcloud-browser-storage/blob/main/LICENSE)
 [![REUSE status](https://api.reuse.software/badge/github.com/nextcloud-libraries/nextcloud-browser-storage)](https://api.reuse.software/info/github.com/nextcloud-libraries/nextcloud-browser-storage)
+
+> Scoped [Web Storage API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API) (`localStorage`) wrapper for Nextcloud apps and libraries
+
+Using `localStorage` directly in Nextcloud apps is risky due to potential key conflicts.
+
+```ts
+// ❌ Could conflict with other apps
+localStorage.setItem('favorite_emoji', '💙')
+```
+
+`@nextcloud/browser-storage` provides a drop-in replacement that scopes storage keys to prevent collisions.
+
+## Installation
+
+```sh
+npm install @nextcloud/browser-storage
+```
+
+## Usage
+
+Add a new module to create and export the browser storage instance.
+
+```ts
+// 📁 browserStorage.ts
+
+import { getBuilder } from '@nextcloud/browser-storage'
+
+// Use you application id
+export const browserStorage = getBuilder('my-app-id')
+  .persist()
+  .build()
+
+// Or without `.persist()` if you need a `sessionStorage` wrapper instead of a `localStorage`
+export const browserSessionStorage = getBuilder('my-app-name').build()
+```
+
+Use `browserStorage` as `localStorage` (or `sessionStorage`) replacement.
+
+```ts
+import { browserStorage } from './path/to/browserStorage.ts'
+
+// ✅ No risk to conflict with other apps
+// Actual key: `nextcloud_per_bXktYXBwLW5hbWU=_favorite_emoji`
+
+const favoriteEmoji = browserStorage.getItem('favorite_emoji')
+browserStorage.setItem('favorite_emoji', '💙')
+browserStorage.removeItem('favorite_emoji')
+browserStorage.clear()
+```
+
+**Note:** some Web Storage API is not available yet
+
+```ts
+// 🚧 Not available yet
+browserStorage.key('favoriteEmoji') 
+browserStorage.length
+
+// 🚧 Listens to all Web Storage changes
+window.addEventListener('storage', () => {})
+```
+
+## API Reference
+
+[https://nextcloud-libraries.github.io/nextcloud-browser-storage/](https://nextcloud-libraries.github.io/nextcloud-browser-storage/)