Add safer isArray function #3606
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I extracted this utility function from #3207 to make TypeScript
isArray()checks safer by preserving the element type, not assuming they'reany.TypeScript's built-in types for
Array.isArray()incorrectly usesany[]. It should useunknown[]. The consequence of usingArray.isArray()is that even if you've narrowed a value to a more specific type, TS will treat it asanyafter the check, which effectively disables type-checking.In this PR, as a demonstration, I only converted a few call sites until I hit one that had a cascading effect that triggered a type error near the call site. In
massageFormats(), thenew Vector3(a[0], a[1], a[2])became an error since TS could no longer assume thata[i]wasany. I addressed it by making themassageFormats()function parameter type more accurate, and this cascaded to the caller of that, where I added an early return.Relevant issues: