Transaction options

Use the IsolationLevel enum for autocomplete and typo-free values (its members map to TypeORM's isolation-level literals, so a raw string still works too):

import { IsolationLevel, NestjsTypeormModule, Transactional } from '@nestjs-transactions/typeorm';

NestjsTypeormModule.forRoot({
  /* ...database options... */
  defaultTxOptions: { isolationLevel: IsolationLevel.REPEATABLE_READ },
});

// per call — options are typed for TypeORM, no type argument needed:
@Transactional({ isolationLevel: IsolationLevel.SERIALIZABLE })

Resolve the options asynchronously (e.g. from ConfigService) with forRootAsync — the factory returns the combined options (database + defaultTxOptions) and runs exactly once:

NestjsTypeormModule.forRootAsync({
  inject: [ConfigService],
  useFactory: (config: ConfigService) => ({
    url: config.get('DATABASE_URL'),
    type: 'postgres',
    defaultTxOptions: { isolationLevel: config.get('DB_ISOLATION') },
  }),
});

In forRootAsync, name and enableTransactionProxy must be static (on the outer options object, not returned by the factory) — DI tokens are computed at module-definition time. forRootAsync is factory-only: @nestjs/typeorm's useClass/useExisting forms are not supported (wrap such a provider in useFactory/inject instead).

Kept in sync with TypeORM

IsolationLevel is kept in lockstep with TypeORM's own isolation-level literal type via a compile-time assertion — if TypeORM changes its literals, the type check fails at build time rather than drifting silently.