fix: readme

README.md

@@ -1,6 +1,6 @@
 # grammy-named-session
 
-grammy-named-session
+Named session for grammY. Works the same way as [built-in session](https://grammy.dev/plugins/session.html) but allows you to set custom name for data access.
 
 ![GitHub CI](https://img.shields.io/github/actions/workflow/status/vlad-yakovlev/grammy-named-session/ci.yml?branch=main&label=github-ci)
 [![Codecov](https://img.shields.io/codecov/c/github/vlad-yakovlev/grammy-named-session/main)](https://codecov.io/gh/vlad-yakovlev/grammy-named-session)
@@ -15,5 +15,57 @@ npm install grammy-named-session
 ## How to use
 
 ```ts
-// TBD
+import { Bot, Context } from 'grammy';
+import { namedSession } from 'grammy-named-session';
+
+interface Item {
+  id: string
+  value: string
+}
+
+interface MyState {
+  items: Item[]
+  users: Record<number, string>
+}
+
+interface MyContext extends Context {
+  myState: MyState
+}
+
+const myStateMiddleware = (dirName: string) => {
+  return namedSession<MyContext, 'myState'>({
+    // type MaybePromise<T> = Promise<T> | T
+
+    // Initial data, required
+    // (ctx: MyContext) => MaybePromise<MyContext['myState']>
+    getInitial: () => ({
+      items: [],
+      users: {},
+    }),
+
+    // Session key, required
+    // (ctx: MyContext) => MaybePromise<string | undefined>
+    getSessionKey: (ctx) =>
+      ctx.chat?.id === undefined ? undefined : `my_${ctx.chat.id}`,
+
+    // Storage adapter, required
+    // (ctx: MyContext) => MaybePromise<StorageAdapter<MyContext['myState']>>
+    getStorage: () => new FileAdapter({ dirName }),
+
+    // Access name, must be the same as in the types, required
+    // string
+    name: 'myState',
+  })
+}
+
+(async () => {
+  const bot = new Bot<MyContext>('<bot-token>');
+
+  bot.use(myStateMiddleware('db/v1'));
+
+  bot.command('start', async (ctx) => {
+    // Access data as usual but with custom name
+    await ctx.mySession.users[ctx.from.id] = ctx.from.first_name;
+  });
+})()
 ```