backend/tsconfig.json

{
  "compilerOptions": {
    "target": "es2017",
    "module": "commonjs",
    "rootDir": "./src",
    "outDir": "./build",
    "esModuleInterop": true,
    "strict": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata":true
  }
}