@terminals-tech/core

Time travel for web apps. Context memory for AI agents. 100 lines of TypeScript.

What This Is

A minimal event sourcing system extracted from production code. Every user action becomes an immutable event. State is computed by replaying events. Navigate to any point in time instantly.

Installation

npm install @terminals-tech/core

3-Minute Setup

import { EventStore } from '@terminals-tech/core'

// Define your events
type MyEvent = 
  | { type: 'increment'; payload: { amount: number } }
  | { type: 'reset' }

// Define your state
type MyState = { count: number }

// Create reducer
const reducer = (state: MyState, event: MyEvent): MyState => {
  switch (event.type) {
    case 'increment': 
      return { count: state.count + event.payload.amount }
    case 'reset': 
      return { count: 0 }
    default: 
      return state
  }
}

// Initialize store
const store = new EventStore<MyEvent, MyState>(
  { count: 0 },
  reducer
)

// Use it
store.append({ type: 'increment', payload: { amount: 5 } })
console.log(store.project()) // { count: 5 }

store.undo()
console.log(store.project()) // { count: 0 }

store.redo()
console.log(store.project()) // { count: 5 }

React Integration

import { useEventStore } from '@terminals-tech/core/react'

function Counter() {
  const { state, dispatch, undo, redo, canUndo, canRedo } = useEventStore<MyEvent, MyState>(
    { count: 0 },
    reducer
  )

  return (
    <>
      <div>Count: {state.count}</div>
      <button onClick={() => dispatch({ type: 'increment', payload: { amount: 1 } })}>+1</button>
      <button onClick={undo} disabled={!canUndo}>Undo</button>
      <button onClick={redo} disabled={!canRedo}>Redo</button>
    </>
  )
}

Agent Context Management

// Give agents perfect memory
const agentStore = new EventStore<ConversationEvent, ConversationState>(
  initialState,
  conversationReducer
)

// Get context window for LLM
const recentEvents = agentStore.getEvents().slice(-50)
const context = recentEvents.map(e => e.payload.message).join('\n')

// Navigate to specific moment
agentStore.navigateToTime(timestamp)

// Fork for exploring alternatives
const alternateTimeline = agentStore.fork()

Performance

• 10,000 events: <50ms replay time
• Memory: ~100 bytes per event
• Storage: Automatic compression for localStorage
• Network: ~100 bytes per event over WebSocket

Core Concepts

1. Events are facts - Immutable, timestamped, ordered
2. State is derived - Always computed from events
3. Time is navigable - Move to any point instantly
4. History is forkable - Create alternate timelines

Why This Pattern Works

• Debugging: See exactly what happened when
• Undo/Redo: Built-in, unlimited levels
• Persistence: Save/load entire session history
• Testing: Replay exact user sequences
• AI Training: Perfect interaction recordings

Production Ready

This is extracted from Journey, a consciousness exploration app where every thought is an event. Currently handling 1000+ events per session with zero performance issues.

License

The core @terminals-tech/core package is licensed under the MIT License.

Other packages in the Terminals ecosystem, such as @terminals-tech/replay and @terminals-tech/sync, may have different, commercial licenses. Please see the respective packages for their specific licensing terms.

---

MIT License

Copyright (c) 2024 Intuition Labs