The right answer is probably to convert your files to typescript but this answer assumes you have time to completely convert your existing js files to ts. If for some reason you don't, they should still work pretty well as partially converted ts files you just might have to take some conversion shortcuts.
I would only recommend doing this with existing known good working js files and only if you can't take the time to convert them which is why I am assuming you are asking the question.
copy your javascript *.js file content into new typescript *.ts files.
resolve all the lint complaints (you can err on the side of flexibility for your JS code)
i.e. using
// @ts-ignore
and the "any" type only when necessary
export the things used by your other files in your new ts files
i.e.
export {varible}
import those things by the dependent files i.e.
import {varible} from "./variableFile"
this should resolve your import order issues.