stream: eos make const state const

writable & readable is based on type and is not actual
state, treat them as such.

Backport-PR-URL: #32178
PR-URL: #32031
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/streams/end-of-stream.js

@@ -47,9 +47,9 @@ function eos(stream, opts, callback) {
 
   callback = once(callback);
 
-  let readable = opts.readable ||
+  const readable = opts.readable ||
     (opts.readable !== false && isReadable(stream));
-  let writable = opts.writable ||
+  const writable = opts.writable ||
     (opts.writable !== false && isWritable(stream));
 
   const onlegacyfinish = () => {
@@ -59,35 +59,31 @@ function eos(stream, opts, callback) {
   let writableFinished = stream.writableFinished ||
     (stream._writableState && stream._writableState.finished);
   const onfinish = () => {
-    writable = false;
     writableFinished = true;
-    if (!readable) callback.call(stream);
+    if (!readable || readableEnded) callback.call(stream);
   };
 
   let readableEnded = stream.readableEnded ||
     (stream._readableState && stream._readableState.endEmitted);
   const onend = () => {
-    readable = false;
     readableEnded = true;
-    if (!writable) callback.call(stream);
+    if (!writable || writableFinished) callback.call(stream);
   };
 
   const onerror = (err) => {
     callback.call(stream, err);
   };
 
   const onclose = () => {
-    let err;
     if (readable && !readableEnded) {
       if (!stream._readableState || !stream._readableState.ended)
-        err = new ERR_STREAM_PREMATURE_CLOSE();
-      return callback.call(stream, err);
+        return callback.call(stream, new ERR_STREAM_PREMATURE_CLOSE());
     }
     if (writable && !writableFinished) {
       if (!isWritableFinished(stream))
-        err = new ERR_STREAM_PREMATURE_CLOSE();
-      return callback.call(stream, err);
+        return callback.call(stream, new ERR_STREAM_PREMATURE_CLOSE());
     }
+    callback.call(stream);
   };
 
   const onrequest = () => {

test/parallel/test-stream-finished.js

@@ -181,7 +181,7 @@ const { promisify } = require('util');
   const streamLike = new EE();
   streamLike.readableEnded = true;
   streamLike.readable = true;
-  finished(streamLike, common.mustCall);
+  finished(streamLike, common.mustCall());
   streamLike.emit('close');
 }