Should we continue the TypeScript migration in v6?

[ephys]

Issue Creation Checklist

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Issue Description

We're getting issues from users that were using /lib about breaking changes in the last release:

• Typescript 4.5.4 does not like sequelize-ESM imports in v6.12 #13791
• Export assignment cannot be used in /sequelize/lib/operators.ts #13803
• operators.ts instead of operators.js file showing up on npm install #13788

I think the TypeScript migration is going to keep breaking internal things which could impact a lot of projects, because:

• export default does not produce the same code as module.exports = (The workaround to which is weird).
• Files move around, breaking imports.
• Users accidentally importing from /types are going to have TS issues (not as bad).

I'm opening this issue to pick the path forward regarding the migration:

• option 1: we consider changes in /lib to not be breaking changes because it's internal.
• option 2: we postpone the migration to v7, where we'll also block importing /lib.
• option 3: we continue migration in v6, but we try to keep /lib like it were.

[ephys]

Closing this, we already have a thread for this that I didn't notice 🤦‍♀️