Lib

The lib folder contains various modules and utilities essential for the operation of the Ledger module. Below are the main files and folders:

events.ts

The events.ts file defines functions for creating custom Nostr events. These events are crucial for communicating transactions and states to the Nostr system. Here are some key functions:

txOkEvent(tx: ITransaction): NostrEvent

Creates a Nostr event after successfully processing a transaction.

const tx = { /* ... */ };
const nostrEvent = txOkEvent(tx);

lastHandled.ts

The lastHandled.ts file contains a LastHandledTracker class that keeps track of the most recent handled Nostr events. This is essential to avoid duplicate event processing. Here's how to use it:

LastHandledTracker

const tracker = new LastHandledTracker(readNDK, writeNDK, ['handler1', 'handler2']);
await tracker.fetchLastHandled();

transactions.ts

The transactions.ts file defines functions and types related to transactions. Some key functions include:

getTxHandler(ctx: Context, ntry: number, txType: TransactionType, handler: Function)

Creates an event handler for a specific transaction.

const handler = getTxHandler(ctx, 0, TransactionType.INBOUND, myTransactionHandler);

utils.ts

The utils.ts file contains general-purpose functions and utilities used throughout the module. Some of the functions include:

setUpRoutes(router: Router, path: string): Router

Configures Express router paths based on files in a specific location.

const router = express.Router();
setUpRoutes(router, './routes');

Middlewares

The middlewares folder contains common middleware functions. Some of them are:

error.middleware.ts

import { errorHandler } from '@lib/middlewares/error.middleware';
 
app.use(errorHandler);
 

not-found.middleware.ts

import { notFound } from '@lib/middlewares/not-found.middleware';
 
app.use(notFound);