As you noted, @types/node includes only a stub for the webcrypto interface. One workaround is to extend the crypto module declaration to declare webcrypto.subtle as SubtleCrypto from the DOM type definitions:

// src/types/index.d.ts

declare module "crypto" {
  namespace webcrypto {
    const subtle: SubtleCrypto;
  }
}

This allows writing a module like:

// src/digest.ts:

import * as crypto from "crypto";

// subtle has type SubtleCrypto, from the DOM type definitions
const { subtle } = crypto.webcrypto;

// Generate a cryptographic digest of the given message
export async function digest(message?: string, algorithm = "SHA-512") {
  const encoder = new TextEncoder();
  const data = encoder.encode(message);
  const hash = await subtle.digest(algorithm, data);
  return hash;
}

To use SubtleCrypto, the project must enable the DOM type definitions by adding dom to the lib array in tsconfig.json. For example, with the following packages installed:

$ npm install -D typescript@4.6 @types/node@17 @tsconfig/node17

and a tsconfig.json containing:

{
  "extends": "@tsconfig/node17/tsconfig.json",
  "compilerOptions": {
    "lib": ["dom"],
    "outDir": "dist",
    "typeRoots": ["./node_modules/@types", "./src/types"]
  },
  "include": ["src/**/*"],
  "exclude": ["dist", "node_modules"]
}

you can write an entrypoint that calls digest and prints the result:

// src/index.ts

import { digest } from "./digest";

const message = "Hello, World!";

(async () => {
  const digestBuffer = await digest(message);
  console.log(Buffer.from(new Uint8Array(digestBuffer)).toString("hex"));
})();

This builds and runs, like:

$ npx tsc && node dist/index.js
374d794a95cdcfd8b35993185fef9ba368f160d8daf432d08ba9f1ed1e5abe6cc69291e0fa2fe0006a52570ef18c19def4e617c33ce52ef0a6e5fbe318cb0387