You might want to try tweaking the tsconfig for your client to "include" the file in the server which you're importing into the client to get types. https://www.typescriptlang.org/tsconfig#include
From allowJs to useDefineForClassFields the TSConfig reference includes information about all of the active compiler flags setting up a TypeScript project.
Looks like you've got a custom repo setup there so it's hard to give much more advice, but I'd be focusing on tsconfig setup first if I had this problem