How to declare a module in TypeScript?

Question

Node.js

This is the first time I've encountered this problem, and I don't really understand how it is solved. Found something like:
jquery.d.ts

declare let $: JQuery;
export default $;

,
but I do not quite understand how to write it correctly and where.
npm didn't find the declaration npm i --save-dev @types/mongoose-beautiful-unique-validation for it .
I write a server on a node using typescript, then I compile it into .js, in the src directory with the server file I created the src/server.d.ts file and wrote the following there:

declare module 'mongoose-beautiful-unique-validation';
export default require('mongoose-beautiful-unique-validation');

But I get an error: declare module 'mongoose-beautiful-unique-validation
How to properly declare such files?

Answer 1

It is possible to prescribe the source of typings in tsconfig.json. It will be more convenient to create some directory in the root, for example typings, and put all custom *.d.ts files in it. However,
the problem here is that this will remove support for other typings from ` @types/* ` and will need to be added to the array manually.

{
   "compilerOptions": {
       "typeRoots" : ["./node_modules/@types", "./typings"]
   }
}

https://www.typescriptlang.org/docs/handbook/tscon...