Suboptimal type hinting

[codpro2005]

Example:

const res = typedRegExp('()?').exec('');
//   ?^ StrictRegExpExecArrayForHasIndices<false, ""> | null

[codpro2005]

I didn't focus on the representation of types, nor am I familiar with best practices in that area, so some types might look messy. Feedback is very welcome.