Issue Description

Starting from the 0.3.0 version, CLI requires to specify the file with DataSource instance instead of ormconfig. When I am trying to export async created DataSource it fails

Expected Behavior

Command ran successfully

Actual Behavior

Command failed with error: Error: Given data source file must contain export of a DataSource instance

Steps to Reproduce

Have your DataSource defined in the file:

const buildDataSource = async () => {
  // Provided config-like functionality just for example, it will fail anyway with just async function
  const dbConfig = await config.get('database');

  return new DataSource({
    type: 'mysql',
    host: dbConfig.host,
    port: 3306,
    username: dbConfig.username,
    password: dbConfig.password,
    database: dbConfig.database,
    logging: true,
    entities: typeormEntities,
    migrations: [ './src/components/database/migrations/**/*.ts' ]
  })
};

export default buildDataSource();

This works though:

const buildDataSource = () => {
  return new DataSource({
    type: 'mysql',
    host: '127.0.0.1',
    port: 3306,
    username: 'test',
    password: 'test',
    database: 'test',
    logging: true,
    entities: typeormEntities,
    migrations: [ './src/components/database/migrations/**/*.ts' ]
  })
};

export default buildDataSource();

My Environment

Relevant Database Driver(s)

I tested with mysql only but I do not think it is a driver problem at all

Are you willing to resolve this issue by submitting a Pull Request?

• ✖️ Yes, I have the time, and I know how to start.
• ✖️ Yes, I have the time, but I don't know how to start. I would need guidance.
• ✖️ No, I don’t have the time, but I can support (using donations) development.
• ✅ No, I don’t have the time and I’m okay to wait for the community / maintainers to resolve this issue.