Error during migration generation: Error: Given data source file must contain export of a DataSource instance

Using latest version of TypeORM: 0.3.9 with NestJS.

While I'm trying to generate migration with following command:

npm run typeorm migration:generate -- ./migrations/Init -o -d ormconfig.js

Getting error:

Error during migration generation:
Error: Given data source file must contain export of a DataSource instance

Here is my DataSource file:

ormconfig.js

var dbConfig = {
  synchronize: false,
  migrations: ['migrations/*.js'],
  cli: {
    migrationsDir: 'migrations',
  },
};

switch (process.env.NODE_ENV) {
  case 'development':
    Object.assign(dbConfig, {
      type: 'sqlite',
      database: 'db.sqlite',
      entities: ['**/*.entity.js'],
    });
    break;
  case 'test':
    Object.assign(dbConfig, {
      type: 'sqlite',
      database: 'test.sqlite',
      entities: ['**/*.entity.ts'],
      migrationsRun: true,
    });
    break;
  case 'production':
    Object.assign(dbConfig, {
      type: 'postgres',
      url: process.env.DATABASE_URL,
      migrationsRun: true,
      entities: ['**/*.entity.js'],
      ssl: {
        rejectUnauthorized: false,
      },
    });
    break;
  default:
    throw new Error('unknown environment');
}
module.exports = dbConfig;



Also TypeORM script snippet from:

package.json

  "scripts": {
    "typeorm": "cross-env NODE_ENV=development node --require ts-node/register ./node_modules/typeorm/cli.js"
  },