joplin/packages/app-desktop/global.d.ts

// Declare codemirror module so that we can import it using the import syntax.
// This also means it will implicitly have the any type, which is necessary because
// of the flexible manner that codemirror is made https://discuss.codemirror.net/t/basic-codemirror-configuration-in-typescript-project/2047/2
declare module 'codemirror';