Migrate to Lerna & publish libdefs to NPM

What we gain with this?

• Lerna setup allows us to publish library definitions to NPM.
• Using NPM allows to utilize npm dependencies for libdef dependencies.
• You can live without flow-typed CLI if you want to

What it requires?

• Lerna repo format (half-done)
• Lerna setup
• NPM namespace (done by @GAntoine : https://www.npmjs.com/org/flowtyped)
• Test runner needs to be migrated to monorepo
• CI setup to publish libdefs to NPM
• Publish libdefs to NPM

Open questions:

• How the libdefs should be named? DefinitelyTyped uses "@types/uuid": "^3.4.2", way of naming. The problem with that is that Flow moves fast and we need to support multiple Flow versions for different libdefs. How to achieve that?

  • Perhaps the naming could be something like: "@flowtyped/uuid-flow_v0.32.x-": "^3.4.2" ?
  • Support only latest Flow version
    • Is this feasible? Most likely not since so many people lack multiple versions behind.

• Should CLI & test runner be split into own repo?

Some earlier plans: https://docs.google.com/document/d/1bR1k70q5xZfajlbbCJR_ZYC-UAU-aH1qUY54RxafNGY/edit

Some experimenting: https://github.com/flow-typed/flow-typed/compare/master...villesau:run-tests-against-experimental-folder

[zeorin]

What about using tags to mark which flow version ranges a libdef version is compatible with? That way people that need to remain on an older version of flow can get the latest version of the libdef that’s still compatible with their flow version.

[jamesisaac]

I’m not sure you need Lerna for this. It would add unnecessary boilerplate to each typedef folder, and probably not something Lerna is designed for anyway (dozens of packages, yes; 100s/1000s, no).

How about keeping the folder structure like it is now, with a script that programmatically adapts each folder to the relevant package(s) and publishes to npm. Afaik this is how TypeScript does it.