gistfile1.js

// ---------------------------------------------------------
// Bun.serve
const server =  Bun.serve({ 
    port: 0,
    fetch: async (req) => {
    const url = new URL(req.url);
    switch (url.pathname) {
      case "/json":
        const jsonResponse = {
          message: "Hello, World!",
          number: 5,
          literal: `(${4}+${4})*${21.2}/${2}=${84.8}`
        };
        return new Response(JSON.stringify(jsonResponse), {
            status: 200,
            headers: {
                "content-type": "application/json; charset=utf-8",
            }
        });
        break;
      default:
        return new Response("Not found", {
          status: 404
        });
        break;
    }
  }
});
// ---------------------------------------------------------
// Deno.serve
// Start a HTTP server using Deno.serve
const server =  Deno.serve(
  { 
    port: 0
  }, 
  async (req) => {
    const url = new URL(req.url);
    switch (url.pathname) {
      case "/json":
        const jsonResponse = {
          message: "Hello, World!",
          number: 5,
          literal: `(${4}+${4})*${21.2}/${2}=${84.8}`
        };
        return new Response(JSON.stringify(jsonResponse), {
            status: 200,
            headers: {
                "content-type": "application/json; charset=utf-8",
            }
        });
        break;
      default:
        return new Response("Not found", {
          status: 404
        });
        break;
    }
  });