Do not require specifying "void" and "Promise<void>" return types

[ry]

We should strive for concise code. void and Promoise<void> return types are unnecessary boilerplate.

Example:

Deno.test({
  name: "Worker with top-level-await",
  fn: async function (): Promise<void> {  // <--- HERE
    const promise = deferred();
    const worker = new Worker(
      new URL("./worker_with_top_level_await.ts", import.meta.url).href,
      { deno: true, type: "module" },
    );
    worker.onmessage = (e): void => {    // <--- HERE
      console.log("received from worker", e.data);
      worker.postMessage("from main");
      promise.resolve();
    };
    await promise;
    worker.terminate();
  },
});

[kitsonk]

I believe we dropped the linting rule requiring explicit return type annotations. I will check later but I believe this compiles and passes linting:

Deno.test({
  name: "Worker with top-level-await",
  aync fn() {
    const promise = deferred();
    const worker = new Worker(
      new URL("./worker_with_top_level_await.ts", import.meta.url).href,
      { deno: true, type: "module" },
    );
    worker.onmessage = (e) => {
      console.log("received from worker", e.data);
      worker.postMessage("from main");
      promise.resolve();
    };
    await promise;
    worker.terminate();
  },
});

[kitsonk]

@ry I checked, the following passes type checking and deno lint fine:

import { deferred } from "https://deno.land/std@0.81.0/async/deferred.ts";

Deno.test({
  name: "Worker with top-level-await",
  async fn() {
    const promise = deferred();
    const worker = new Worker(
      new URL("./worker_with_top_level_await.ts", import.meta.url).href,
      { deno: true, type: "module" },
    );
    worker.onmessage = (e) => {
      console.log("received from worker", e.data);
      worker.postMessage("from main");
      promise.resolve();
    };
    await promise;
    worker.terminate();
  },
});

Any concerns with that?