We've faced the pain of maintaining flow definitions and trying to help with flow-typed long enough. It's about time we switch to typescript. Many of us have seen the writing on the wall and keep talking about it. The community just isn't in flow. Time to take action.

Since we're on babel 7, we can start incrementally adopting typescript package by package.

For larger packages like @nteract/core we might want to try https://medium.com/entria/incremental-migration-to-typescript-on-a-flowtype-codebase-515f6490d92d

If you'd like to help out, start with a single small package. We'll use the first one (#3465) as a reference to the rest.

We are all done with the packages* except for the data explorer, styles, styleguide components, and webpack configurator. Data explorer has an in-progress PR #3874. styles probably isn't worth it. Styleguide components... could probably be brought down out of packages as its just for the docs. That or we make those official components in some way. Webpack configurator may not be necessary soon as pointed out by @captainsafia as part of the nteract play PR.

As for application conversion:

• Desktop PR: Convert desktop app to typescript #3900
• Jupyter Extension: Started in Typescript jupyter-extension conversion #3914, surfaced errors in correct the tsconfig for jupyter extension #3917
• Play: Done in Migrate nteract play to TypeScript #3842
• Commuter: not started migrating back to nteract/commuter

Additional efforts:

• adapt our docgen setup to using typescript