What does the ‘as’ clause in a mapped type key remapping enable? type Example = { [K in keyof T as K extends string ? K : never]: T[K] }

Question

TypeScript Associate — Hard

What does the ‘as’ clause in a mapped type key remapping enable? type Example = { [K in keyof T as K extends string ? K : never]: T[K] }

Accepted Answer

The 'as' clause in a mapped type key remapping allows for filtering out non-string keys by remapping them to never. This ensures that only string keys are included in the mapped type.