This is the last callsite of keyMirror! It removes 0.5k gzipped :)
The only trick with this one is that ReactTestUtils actually iterates over the list of all the events. Instead of duplicating the logic, I used the $Enum feature of flow that lets us statically extract out the type from the dynamic value. Inside of react-dom we're no longer requiring the file directly so it doesn't bloat the file size, and we still get to have static typing, best of both worlds!
This one is interesting because we have transaction objects being passed around everywhere in the codebase but there's actually no Transaction class. It's a "mixin" that comes to life by being Object.assigned to the prototype of a real "class" (before class was cool!). Therefore, we can't just say `var Transaction = require('Transaction'); (transaction: Transaction) => { }` because it would be the object that contains a mixin and not an instance of a transaction.
The trick I use is to export `TransactionType` and alias it to `Transaction` in the file as it doesn't actually require transaction. In case they do, we'll figure it out, but in the few files I looked at, it doesn't seem to be the case.
For the perform function, it actually typechecks pretty well!
This one was really interesting to type as it's doing a lot of unusual JavaScript. Fortunately flow is now pretty kick ass and I've been able to mostly type it. The only missing piece is that it won't check the constructor arguments.
If you are a fb employee, you can follow the discussion here: https://www.facebook.com/groups/flowtype/permalink/1132359430146004/
Incrementally type ReactInstance by adding the types of attach/detachRef.
I moved isValidOwner as a function inside of the file since it's never used externally.
This one involves a bit more work as I added "phantom" flow types to a bunch of places where the type is a ReactPropTypeLocations even though those files are not `@flow` yet.
A good side effect is that `ReactPropTypeLocationNames` keys are now correctly typed, this means that they cannot go out of sync without breaking flow :)
Flow doesn't really support the concept of variables that are non-null but only inside of a `__DEV__` block. There's an internal post about it ( https://www.facebook.com/groups/flowtype/permalink/1132437726804841/ ) and the conclusion is that we should force it to be non-null and trust the developer to put the proper DEV checks in place.
We need to export FlushHistory type and I submitted a PR on flow to fix the type of console.table which is too restrictive.
I'm already starting to see the benefits of flow, I can look at random variables in the code and flow knows what shape the objects are! It's really useful to try and understand what's going on :)
In Type ReactComponentTreeHook #7504, I merged even though travis didn't report green (travis for all the fb repos has been backlogged like crazy since this morning) by manually doing `npm test` and `npm run flow` but I didn't ensure that lint was all green.
@millermedeiros pinged me about it so here's a quick fix
For this one, I wanted to type a non-trivial piece of the codebase and ran into the fact that we do not have types for ReactElement nor ReactInstance, so I had to create them.
I'll add comments inline