Function proxyResponse

src/frameworks/utils.ts:76–161

(
  req: IncomingMessage,
  res: ServerResponse,
  next: () => void,
)

 * it back to the client.
 */
export function proxyResponse(
  req: IncomingMessage,
  res: ServerResponse,
  next: () => void,
): ServerResponse {
  const proxiedRes = new ServerResponse(req);
  // Object to store the original response methods
  const buffer: [
    string,
    Parameters<ServerResponse["write" | "setHeader" | "removeHeader" | "writeHead" | "end"]>,
  ][] = [];

  // Proxy the response methods
  // The apply handler is called when the method e.g. write, setHeader, etc. is called
  // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/apply
  // The target is the original method
  // The thisArg is the proxied response
  // The args are the arguments passed to the method
  proxiedRes.write = new Proxy(proxiedRes.write.bind(proxiedRes), {
    apply: (
      target: ServerResponse["write"],
      thisArg: ServerResponse,
      args: Parameters<ServerResponse["write"]>,
    ) => {
      // call the original write method on the proxied response
      target.call(thisArg, ...args);
      // store the method call in the buffer
      buffer.push(["write", args]);
    },
  });

  proxiedRes.setHeader = new Proxy(proxiedRes.setHeader.bind(proxiedRes), {
    apply: (
      target: ServerResponse["setHeader"],
      thisArg: ServerResponse,
      args: Parameters<ServerResponse["setHeader"]>,
    ) => {
      target.call(thisArg, ...args);
      buffer.push(["setHeader", args]);
    },
  });
  proxiedRes.removeHeader = new Proxy(proxiedRes.removeHeader.bind(proxiedRes), {
    apply: (
      target: ServerResponse["removeHeader"],
      thisArg: ServerResponse,
      args: Parameters<ServerResponse["removeHeader"]>,
    ) => {
      target.call(thisArg, ...args);
      buffer.push(["removeHeader", args]);
    },
  });
  proxiedRes.writeHead = new Proxy(proxiedRes.writeHead.bind(proxiedRes), {
    apply: (
      target: ServerResponse["writeHead"],
      thisArg: ServerResponse,
      args: Parameters<ServerResponse["writeHead"]>,
    ) => {
      target.call(thisArg, ...args);