Feature summary (what you would like to be able to do and where):
Currently it seems like most of the code in the jquery.i18n library is being documented with JSDoc comments, meaning that generating .d.ts files (aka typescript declaration files) would not require too much work.
The generated .d.ts files could be published as part of the npm package for use by end users (such as myself).
Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
Developing a Typescript-based userscript with the jquery.i18n library
Benefits (why should this be implemented?):
As a userscript developer working with the Mediawiki JS API, having typescript declaration files is extremely helpful to ensure the type-safety of my project and also to use autocomplete in my IDE.