clean up old code

node/_stream.d.ts

@@ -3,6 +3,7 @@
 
 // Forked from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/4f538975138678878fed5b2555c0672aa578ab7d/types/node/stream.d.ts
 
+import { Buffer } from "./_buffer.d.ts";
 import { Abortable, EventEmitter } from "./_events.d.ts";
 import {
   Buffered,
@@ -1477,5 +1478,5 @@ interface Pipe {
 }
 
 // These have to be at the bottom of the file to work correctly, for some reason
-export { _uint8ArrayToBuffer } from "./internal/streams/_utils.ts";
-export { isUint8Array as _isUint8Array } from "./internal/util/types.ts";
+export function _uint8ArrayToBuffer(chunk: Uint8Array): Buffer;
+export function _isUint8Array(value: unknown): value is Uint8Array;

node/_stream.mjs

@@ -18,6 +18,7 @@ import {
   ERR_STREAM_PREMATURE_CLOSE,
 } from "./internal/errors.ts";
 import { destroy } from "./internal/streams/destroy.mjs";
+import { isReadableEnded, isWritableEnded } from "./internal/streams/utils.mjs";
 import { validateBoolean, validateObject } from "./internal/validators.mjs";
 
 let process = __Process$;
@@ -34,31 +35,6 @@ function isWritableStream(object) {
   return object instanceof WritableStream;
 }
 
-function isReadableEnded(stream) {
-  if (stream.readableEnded) return true;
-  const rState = stream._readableState;
-  if (!rState || rState.errored) return false;
-  return rState.endEmitted || (rState.ended && rState.length === 0);
-}
-
-function isWritableNodeStream(obj) {
-  return !!(
-    obj &&
-    typeof obj.write === "function" &&
-    typeof obj.on === "function" &&
-    (!obj._readableState || obj._writableState?.writable !== false) // Duplex
-  );
-}
-
-function isWritableEnded(stream) {
-  if (!isWritableNodeStream(stream)) return null;
-  if (stream.writableEnded === true) return true;
-  const wState = stream._writableState;
-  if (wState?.errored) return false;
-  if (typeof wState?.ended !== "boolean") return null;
-  return wState.ended;
-}
-
 Readable.fromWeb = function (
   readableStream,
   options = {},