Optional exclusion (`undefined` case)

[guigaoliveira]

In the readme we have to

delete a?.b
a == null ? true : delete a.b

but we know that

delete undefined // false
delete null // true 

shouldn't it be like this?

delete a?.b
a == null ? false : delete a.b

[rkirsling]

delete undefined is false because it's an attempt to delete the global property called "undefined"; delete void 0, which attempts to delete the value undefined, is true.

When a is nullish, delete a?.b applies the delete operator to the value undefined, hence it's true.

[guigaoliveira]

Got it, thanks!