Use typeORM for interacting with DB

package.json

@@ -17,7 +17,9 @@
     "openai": "^4.77.0",
     "react": "^18",
     "react-dom": "^18",
-    "level": "^7.0.0"
+    "sqlite": "^4.0.25",
+    "sqlite3": "^5.1.7",
+    "typeorm": "^0.3.12"
   },
   "devDependencies": {
     "@types/node": "^20",

src/data-source.ts

@@ -0,0 +1,20 @@
+import { DataSource } from 'typeorm';
+import { Payment } from './entity/Payment';
+
+export const AppDataSource = new DataSource({
+  type: 'sqlite',
+  database: './database.sqlite',
+  synchronize: true,
+  logging: false,
+  entities: [Payment],
+  migrations: [],
+  subscribers: [],
+});
+
+AppDataSource.initialize()
+  .then(() => {
+    console.log('Data Source has been initialized!');
+  })
+  .catch((err) => {
+    console.error('Error during Data Source initialization:', err);
+  });

src/entity/Payment.ts

@@ -0,0 +1,10 @@
+import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';
+
+@Entity()
+export class Payment {
+  @PrimaryGeneratedColumn()
+  id!: number;
+
+  @Column({ unique: true })
+  transactionSignature!: string;
+}

src/utils/verifyPayment.ts

@@ -1,13 +1,12 @@
-import level from 'level';
-
 import { Connection } from '@solana/web3.js';
 import { TOKEN_PROGRAM_ID } from '@solana/spl-token';
 
+import { AppDataSource } from '../data-source';
+import { Payment } from '../entity/Payment';
+
 const SOLANA_RPC_URL = process.env.NEXT_PUBLIC_SOLANA_RPC_URL;
 const SOLANA_WEBSOCKET_URL = process.env.NEXT_PUBLIC_SOLANA_WEBSOCKET_URL;
 
-const db = level('./usedSignaturesDB');
-
 const connection = new Connection(
   SOLANA_RPC_URL,
   {
@@ -18,19 +17,16 @@ const connection = new Connection(
 );
 
 export async function isSignatureUsed(transactionSignature: string): Promise<boolean> {
-  try {
-    await db.get(transactionSignature);
-    return true;
-  } catch (error) {
-    if (error.notFound) {
-      return false;
-    }
-    throw error;
-  }
+  const paymentRepository = AppDataSource.getRepository(Payment);
+  const payment = await paymentRepository.findOneBy({ transactionSignature });
+  return !!payment;
 }
 
 export async function markSignatureAsUsed(transactionSignature: string): Promise<void> {
-  await db.put(transactionSignature, 'used');
+  const paymentRepository = AppDataSource.getRepository(Payment);
+  const payment = new Payment();
+  payment.transactionSignature = transactionSignature;
+  await paymentRepository.save(payment);
 }
 
 export async function verifyPayment(

tsconfig.json

@@ -16,6 +16,8 @@
     "resolveJsonModule": true,
     "isolatedModules": true,
     "jsx": "preserve",
+    "experimentalDecorators": true,
+    "emitDecoratorMetadata": true,
     "plugins": [
       {
         "name": "next"