Destructuring "type parallelism" error in createElement

[potrykus]

snabbdom-pragma/src/index.js

Line 71 in afc9651

return sel(data || {}, children)

If line 69 collects all ...children in an array (e.g. JSX.Element[]), shouldn't ...children be re-splatted into the sel fn on line 71?

As line 71 is now written, sel(, children) gets an extra level of array wrapping with each pass into a Component (at one pass deeper in, JSX.Element[] arrays become JSX.Element[][], with only the zeroth element populated). I believe this is not the intent.

Interestingly the story for sanitizeChildren called on line 73 is different and instructive: Pure text is only ever found through the zeroth element of the rhs OR operand on line 60, but this is different from what a general Component sel fn (line 71) expects I believe (that won't expect an [][]).

Last, line 77 is "saved" (meaning will have no apparent problems), I guess, by line 62's reduceDeep, right? So it also does not suffer the bug of line 71, I guess?

There is a deeper test that I don't know how to write that proves these "type parallelisms" are preserved. I believe that test is full typing!