DataSourceHolder

A TypeORM object which knows the DataSource it belongs to, such as a QueryBuilder, EntityManager, QueryRunner or EntityMetadata. TypeORM 0.3 names that property connection. TypeORM 1 renames it to dataSource and keeps connection as a deprecated alias on some, but not all, of those classes. Code which has to run on both versions therefore reads the DataSource via getDataSource rather than naming either property directly.

type DataSourceHolder = {    connection?: DataSource;    dataSource?: DataSource}