There is types and typesRoot compiler options, which allows you declare types from custom packages. Needs to change detecting whether the package is from external module to handle this.
Actually types from that folders should be in d.ts files, and the tool treats d.ts files as "external" already, so I think no additional action required.
There is
types
andtypesRoot
compiler options, which allows you declare types from custom packages. Needs to change detecting whether the package is from external module to handle this.