A simple example I could recall from the other day is something like this: export type LinkedWorksheetsRecord = Record<WorksheetId, Record<WorksheetId, Refer

A simple example I could recall from the other day is something like this: export type LinkedWorksheetsRecord = Record<WorksheetId, Record<WorksheetId, ReferenceTypeId[]>>; export type LinkedWorksheetsMap = Map<WorksheetId, Map<WorksheetId, ReferenceTypeId[]>>; What I would rather have written instead is however something like this: export type LinkedWorksheets<T> = T<WorksheetId, T<WorksheetId, ReferenceTypeId[]>>; ... const myMap: LinkedWorksheets<Map> = ...; This is however not possible, because `Map` is a type constructor which expects two more type arguments `K, V` until it is a fully applied, concrete type `Map<K, V>`. With a library like this, this is probably possible (unless I've missed something which wouldn't surprise me). It would unfortunately surely be more verbose. Still, I would be against pulling in a dependency only for something like this. The above example is simple I believe, but not exactly a "killer-app". And no, Monads aren't either (if you don't limit effects and don't have do-notation) :P