Install
flow-to-ts
Convert Flow code to TypeScript.
:warning: This is a WIP and many things still do not work properly. There
may also be the odd regression from time to time as work progresses.
The goal of this project is to provide a tool that can translate 95% of Flow
to TypeScript while maintaining a high percentage of the existing type
information. We don't want to convert code and end up with everything using
any. We also want to avoid having to make a lot of manual changes to files
afterwards, e.g. changing SyntheticEvent to React.Event.
Quick start
yarn global add @khanacademy/flow-to-tsflow-to-ts [options] <file globs>
For a comprehensive list of available options, please check out the CLI code.
Playground
https://flow-to-ts.netlify.com
Principles
- when exact translation isn't possible:
- downgrade to
anywhen possible and provide a gentle warning - when it isn't possible to downgrade (e.g.
%checks), remove the syntax
and provide a forceful warning that the code in question will need a human
to convert it manually.
- downgrade to
- best effort to maintain blank lines and the position comments, this isn't
always possible so warn in those situations where we can't, e.g. converting
object type spreads to intersection types.
Contributing
Bugs
Bug reports for converting Flow to TypeScript should include a link to the
playground with an example of a minimal reproducible example of the bug.
Feature Requests
Feature requests are welcome.
Pull Requests
Please make sure there is a GitHub issue first before creating a pull request
except for small things. Also, please sign our Contributor License Agreement.
Pull requests that fix a bug in the conversion code should include one or more
test cases and should have 100% diff coverage.
Dev quick start
git clone [email protected]:Khan/flow-to-ts.git
cd flow-to-ts
git submodule update --depth 1 --init -- babel
cd babel
yarn
cd ..
yarn
yarn test
Helpful resources
- https://github.com/niieani/typescript-vs-flowtype
- https://astexplorer.net/
