How to make externs for npm packages without global pollution

I want to use Closure Compiler to type check for a Node.js project (with CommonJS or ES Module).
It uses many npm packages and they need their externs files for type checking.
Can I make and provide externs for them?

I cannot make it because `module` is not available in externs.
sample: https://github.com/teppeis-sandbox/closure-node-sample1/tree/comment-out-require
Also `contrib/nodejs/*.js` doesn't work for the same reason.

I found a workaround using a global object like [react-externs](https://github.com/steida/react-externs), but it doesn't match the style of Node.

TypeScript supports for this feature with [ambient modules](https://www.typescriptlang.org/docs/handbook/modules.html#ambient-modules) in `d.ts`.
```typescript
declare module "path" {
export function normalize(p: string): string;
export function join(...paths: any[]): string;
export var sep: string;
}
```