@xlsft/grammy-reactive

React-like stateful library for grammY with JSX, hooks, lifecycle, effects, and component error boundaries.

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✨ Features

• ⚛️ JSX component system
• 🪝 React-like hooks API
• 🔁 Stateful rerendering
• 🧠 Persistent component-local hook storage
• 🧹 useEffect with cleanup support
• 💥 Error boundaries for root + nested components
• ⛔ Abortable rerenders via AbortController
• 🧩 Async component support
• 📦 Component path–scoped state isolation
• 🤖 Deep access to grammY context via runtime hooks

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🚀 Quick Start

Installation

# Deno
deno install npm:@xlsft/grammy-reactive

# Bun
bun add @xlsft/grammy-reactive

# npm
npm install @xlsft/grammy-reactive

# pnpm
pnpm add @xlsft/grammy-reactive

# yarn
yarn add @xlsft/grammy-reactive

# vlt
vlt install @xlsft/grammy-reactive

Add JSX runtime to tsconfig.json

{
    "compilerOptions": {
        "module": "ES2022",
        "moduleResolution": "bundler",
        "jsxImportSource": "@xlsft/grammy-reactive/jsx",
        "jsx": "react-jsx",
    },
}

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Basic Message Component

import { Bot, Context } from "grammy";
import { defineMessageHandler, useState, reactive, type ReactiveFlavor } from "@xlsft/grammy-reactive";

const bot = new Bot<ReactiveFlavor<Context>>(process.env.TG_TOKEN!);
bot.use(reactive());

const startHandler = defineMessageHandler(async () => {
    const [count, setCount] = useState(0);

    return (
        <>
            <h>Counter</h>
            <blockquote>
                Value: <b>{count}</b>
            </blockquote>
            <button onClick={() => setCount(c => c + 1)}>
                Increment
            </button>
        </>
    );
});

bot.command("start", startHandler);

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📔 Full documentation

WIP

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🧠 Core Mental Model

Every message handler creates a persistent message runtime instance.

This runtime stores:

• current Telegram message state
• hook values
• effect queue
• cleanup callbacks
• component tree path
• abort controller
• grammY context

Each rerender reuses the same runtime.

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🪝 Hooks API

The framework ships with a familiar React-like hooks layer:

• useState → local reactive state
• useMemo → memoized computed values
• useCallback → stable callback references
• useReducer → complex state transitions
• useEffect → post-commit side effects + cleanup

...etc

All hooks are:

• component-path scoped
• persistent across rerenders
• safe inside async components
• automatically restored by render order

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🔘 Inline Buttons

Inline buttons are a first-class reactive UI primitive.

They behave like component event handlers and automatically participate in the lifecycle runtime.

<button color="primary" onClick={() => setCount(c => c + 1)}>
    Increment
</button>

<button variant="copy" value="Copy this text!">
    Copy what text?
</button>

<button variant="url" url="https://google.com">
    Go to google
</button>

🧩 Stateful Component Example

import {
    defineMessageHandler,
    useEffect,
    useState,
    useContext,
} from "@xlsft/grammy-reactive";

export default defineMessageHandler(async () => {
    const [seconds, setSeconds] = useState(0);
    const ctx = useContext();

    useEffect(() => {
        const interval = setInterval(() => {
            setSeconds(s => s + 1);
        }, 1000);

        return () => clearInterval(interval);
    }, []);

    return <b>Running for {seconds}s</b>;
});

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🔄 Lifecycle Model

The framework uses a render → commit → effects lifecycle.

flowchart TD
    A[Handler / Event] --> B[Render JSX Tree]
    B --> C[Commit to Telegram]
    C --> D[Flush useEffect Queue]
    D --> E[Wait for User Events]
    E -->|setState| B
    E -->|unmount| F[Run Cleanup]
    F --> G[Delete Message]

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🧠 Hook Storage Architecture

Hooks are stored by component path key.

flowchart LR
    A[Runtime] --> B[hooks: Map]
    B --> C[0]
    B --> D[0.0]
    B --> E[0.1]
    C --> F[Parent hooks]
    D --> G[Child A hooks]
    E --> H[Child B hooks]

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This guarantees:

• sibling isolation
• nested component stability
• deterministic hook ordering
• subtree-safe rerenders

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🧬 State Management Principles

1) Component Path Isolation

Each component subtree owns its own hook array.

This prevents collisions between:

<A />
<B />

Both may safely use:

useState()

without shared state.

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2) Functional Updates Preferred

Always prefer:

setCount(prev => prev + 1)

over:

setCount(count + 1)

This avoids stale closures in async effects.

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3) Effects Are Commit-Phase Only

useEffect runs after successful Telegram message update.

This guarantees UI consistency.

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💥 Error Boundaries

The framework automatically catches:

• root handler exceptions
• nested component exceptions
• rerender errors
• effect cleanup errors
• event handler errors

Fallback UI renders InternalError safely.

flowchart TD
    A[Render Component] --> B{Throws?}
    B -->|No| C[Continue Render]
    B -->|Yes| D[Render InternalError]
    D --> E[Commit Fallback UI]

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⛔ Abort + Rerender Semantics

Every message runtime owns its own AbortController.

Before rerender:

1. previous controller is aborted
2. new controller is created
3. stale async updates are cancelled

sequenceDiagram
    participant U as User
    participant R as Runtime
    participant T as Telegram

    U->>R: setState()
    R->>R: abort previous controller
    R->>R: render new tree
    R->>T: editMessageText()
    R->>R: flushEffects()

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📐 Best Practices

✅ Prefer split effects

useEffect(startInterval, []);
useEffect(syncReaction, [seconds]);

instead of mixing unrelated side effects.

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✅ Use reducer for flows

Use useReducer for:

• wizards
• menus
• calculators
• async status machines
• pagination

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✅ Memoize callbacks for child props

const onSave = useCallback(() => save(id), [id]);

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🏗️ Architecture Summary

flowchart TD
    A[defineMessageHandler] --> B[createMessageState]
    B --> C[withRuntime]
    C --> D[createMessageRender]
    D --> E[Telegram Commit]
    E --> F[flushEffects]
    F --> G[cleanupEffects on unmount]

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❤️ Philosophy

The goal is simple:

Bring React-like declarative stateful UI architecture into Telegram bots without losing grammY power.

This library treats a Telegram message as a live reactive UI surface.

State, effects, rerenders, and cleanup behave like a real component runtime.

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📄 License

MIT