Transport - Typed Event Emitter for Actions

A minimal, strongly-typed event system using a LinkedList-based listener registry.
Perfect for handling internal communication between services, modules, or UI logic.

📦 Features

• ✅ Type-safe actions via SendActionMap
• ✅ addListener and removeListener for multiple callbacks
• ✅ once for one-time listeners
• ✅ Minimal and fast LinkedList-based storage
• ✅ Clean integration via module augmentation

🧠 Concept

At its core, the Transport class allows you to send messages (with optional payloads) and register listeners for specific actions. All listeners are scoped to typed keys defined in SendActionMap.

🚀 Getting Started

1. Install

npm install wi-functions-emitter

2. Extend the SendActionMap interface

To register your valid action names, extend the SendActionMap in your app:

// types/transport.d.ts or any global file
import "wi-functions-emitter";

declare module "wi-functions-emitter" {
  interface SendActionMap {
    UPDATE_ADDRESS: true;
    INSERT_ADDRESS: true;
    INSERT_PAYMENT: true;
    INSERT_PAYMENT_CATEGORY: true;
    INSERT_USER: true;
    CHECK_SESSION: true;
    ACTION_LOGIN: true;
    UPDATE_PAYMENT: true;
  }
}

TypeScript will enforce only those keys as valid listenerName or action.

✨ Usage

1. Initialize

import { Transport } from 'wi-functions-emitter';

const transport = new Transport();

2. Add a Listener

transport.addListener("INSERT_USER", ({ action, payload }) => {
  console.log("User inserted:", payload);
});

3. Send a Message

transport.sendMessage({
  action: "INSERT_USER",
  payload: {
    id: 123,
    name: "Alice"
  }
});

4. One-Time Listener

The listener will be removed after the first call:

transport.once("ACTION_LOGIN", ({ action, payload }) => {
  console.log("Login event handled:", payload);
});

5. Remove a Listener

function onSessionCheck({ action }: { action: string }) {
  console.log("Checking session...");
}

transport.addListener("CHECK_SESSION", onSessionCheck);
transport.removeListener("CHECK_SESSION", onSessionCheck);

📚 API Reference

| Method | Description | |------------------------------------------------------------------------|---------------------------------------------------------| | addListener<T>(action: ISendAction, callback: ICallbackFn<T>) | Adds a new listener for the given action. | | removeListener<T>(action: ISendAction, callback: ICallbackFn<T>) | Removes a specific listener. | | once<T>(action: ISendAction, callback: ICallbackFn<T>) | Adds a listener that auto-removes after one call. | | sendMessage<T>(data: ICallbackFnArguments<T>) | Triggers all callbacks associated with the given action. |

🧪 Testing

npm run test