Typeorm CLI not usable - Running CLI returns: TypeError: dataSourceFileExports is not iterable

[Kyle1297]

Issue Description

Expected Behavior

To be able to easily run and generate migrations via typeorm CLI.

Actual Behavior

// include the output in code tags like these!

➜  typeorm-bug git:(master) ✗ npm run typeorm:migrate

> typeorm-bug@1.0.0 typeorm:migrate
> typeorm-ts-node-commonjs migration:run --dataSource ./typeorm.config.ts

Error during migration run:
TypeError: dataSourceFileExports is not iterable
    at Function.loadDataSource (~/typeorm-bug/src/commands/CommandUtils.ts:37:34)
    at async Object.handler (~/typeorm-bug/src/commands/MigrationRunCommand.ts:42:26)

➜  typeorm-bug git:(master) ✗ npm run typeorm:generate --name=Testing                          

> typeorm-bug@1.0.0 typeorm:generate
> typeorm-ts-node-commonjs migration:generate ./src/migration/$npm_config_name --dataSource ./typeorm.config.ts

Error during migration generation:
TypeError: dataSourceFileExports is not iterable
    at Function.loadDataSource (~/typeorm-bug/src/commands/CommandUtils.ts:37:34)
    at async Object.handler (~/typeorm-bug/src/commands/MigrationGenerateCommand.ts:73:26)

Steps to Reproduce

Repo available here: https://github.com/Kyle1297/typeorm-bug.git

1. Run npm i command
2. Run npm start command
3. Run npm run typeorm:migrate and npm run typeorm:generate --name=Testing commands to observe errors

My Environment

Dependency	Version
Operating System	macOS Monterey 12.5.1
Node.js version	x.y.zzz
Typescript version	x.y.zzz
TypeORM version	x.y.zzz

Additional Context

This also occurs across multiple 3+ typeorm versions + in a Node 16 docker container running NestJS as well. For this bug, I removed all this extra stuff to create this minimal, reproducible example.

I previously was working with typeorm version 0.2.31 and things were all good.

Relevant Database Driver(s)

DB Type	Reproducible
aurora-mysql	no
aurora-postgres	no
better-sqlite3	no
cockroachdb	no
cordova	no
expo	no
mongodb	no
mysql	no
nativescript	no
oracle	no
postgres	yes
react-native	no
sap	no
spanner	no
sqlite	no
sqlite-abstract	no
sqljs	no
sqlserver	no

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.

[rbnayax]

This bug was introduced in #8917 where they used (accidentally in my opinion) for...of instead of for...in