feat: add index transaction command and template for it's handler

Signed-off-by: Anmol Sharma <anmolsharma0234@gmail.com>

package.json

@@ -26,6 +26,7 @@
     "@nestjs/common": "^9.0.0",
     "@nestjs/config": "^3.2.2",
     "@nestjs/core": "^10.3.7",
+    "@nestjs/cqrs": "^10.2.7",
     "@nestjs/microservices": "^10.3.7",
     "@nestjs/passport": "^9.0.3",
     "@nestjs/platform-express": "^10.3.7",

src/commands/index-transaction.command.ts

@@ -0,0 +1,18 @@
+export type TransactionInput = {
+    scriptSig: string; // unlocking script
+    witness?: string[]; // witness data
+    prevOutScript: string; // previous output script
+};
+
+export type TransactionOutput = {
+    scriptPubKey: string;
+    value: number;
+};
+
+export class IndexTransactionCommand {
+    constructor(
+        public readonly txid: string,
+        public readonly vin: TransactionInput[],
+        public readonly vout: TransactionOutput[],
+    ) {}
+}

src/handlers/commands/index-transaction.handler.ts

@@ -0,0 +1,11 @@
+import { CommandHandler, ICommandHandler } from '@nestjs/cqrs';
+import { IndexTransactionCommand } from '@/commands/index-transaction.command';
+
+@CommandHandler(IndexTransactionCommand)
+export class IndexTransactionHandler
+    implements ICommandHandler<IndexTransactionCommand>
+{
+    async execute(command: IndexTransactionCommand) {
+        throw new Error(`Method not implemented. Command: ${command}`);
+    }
+}