Flow: Spread with undefined and exact objects

[stropho]

I found a couple of issues with spread operator but most of them seem to have problem with optional values ( https://github.com/facebook/flow/issues/7210 ). This is not the case. The problem is that undefined behaves magically like any

Flow version:
0.96 - and many versions before

Expected behavior

undefined is incompatible with string

Actual behavior

See the following snippet

[lll000111]

Just for fun, here is the same sample code with TypeScript (works as expected there). I use (only) Flow, I'm just curious what the state of the two JS-type projects is.

[mrkev]

I think @jbrown215 is working around spreads right now, he might want to have a look at this.

[jbrown215]

This will be solved when my current project lands. Thanks for the example!

[stropho]

@jbrown215 any approximate time estimate ?

[nmote]

The fixes for spreads have landed, and this has the expected behavior in master.