lib: require a callback for end-of-stream

Make the callback mandatory as mostly done in all other Node.js
callback APIs so users explicitly have to decide what to do in error
cases.

This also documents the options for `Stream.finished()`.

When originally implemented it was missed that Stream.finished() has
an optional options object.

PR-URL: #21058
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Mathias Buus <mathiasbuus@gmail.com>

doc/api/stream.md

@@ -1294,12 +1294,21 @@ implementors should not override this method, but instead implement
 [`readable._destroy()`][readable-_destroy].
 The default implementation of `_destroy()` for `Transform` also emit `'close'`.
 
-### stream.finished(stream, callback)
+### stream.finished(stream[, options], callback)
 <!-- YAML
 added: v10.0.0
 -->
 
 * `stream` {Stream} A readable and/or writable stream.
+* `options` {Object}
+  * `error` {boolean} If set to `false`, then a call to `emit('error', err)` is
+    not treated as finished. **Default**: `true`.
+  * `readable` {boolean} When set to `false`, the callback will be called when
+    the stream ends even though the stream might still be readable.
+    **Default**: `true`.
+  * `writable` {boolean} When set to `false`, the callback will be called when
+    the stream ends even though the stream might still be writable.
+    **Default**: `true`.
 * `callback` {Function} A callback function that takes an optional error
   argument.
 
@@ -2438,7 +2447,7 @@ contain multi-byte characters.
 [zlib]: zlib.html
 [hwm-gotcha]: #stream_highwatermark_discrepancy_after_calling_readable_setencoding
 [pipeline]: #stream_stream_pipeline_streams_callback
-[finished]: #stream_stream_finished_stream_callback
+[finished]: #stream_stream_finished_stream_options_callback
 [stream-_flush]: #stream_transform_flush_callback
 [stream-_read]: #stream_readable_read_size_1
 [stream-_transform]: #stream_transform_transform_chunk_encoding_callback

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

@@ -4,11 +4,10 @@
 'use strict';
 
 const {
+  ERR_INVALID_ARG_TYPE,
   ERR_STREAM_PREMATURE_CLOSE
 } = require('internal/errors').codes;
 
-function noop() {}
-
 function isRequest(stream) {
   return stream.setHeader && typeof stream.abort === 'function';
 }
@@ -23,10 +22,19 @@ function once(callback) {
 }
 
 function eos(stream, opts, callback) {
-  if (typeof opts === 'function') return eos(stream, null, opts);
-  if (!opts) opts = {};
+  if (arguments.length === 2) {
+    callback = opts;
+    opts = {};
+  } else if (opts == null) {
+    opts = {};
+  } else if (typeof opts !== 'object') {
+    throw new ERR_INVALID_ARG_TYPE('opts', 'object', opts);
+  }
+  if (typeof callback !== 'function') {
+    throw new ERR_INVALID_ARG_TYPE('callback', 'function', callback);
+  }
 
-  callback = once(callback || noop);
+  callback = once(callback);
 
   const ws = stream._writableState;
   const rs = stream._readableState;

test/parallel/test-stream-finished.js

@@ -91,8 +91,8 @@ const { promisify } = require('util');
 {
   const rs = fs.createReadStream('file-does-not-exist');
 
-  finished(rs, common.mustCall((err) => {
-    assert.strictEqual(err.code, 'ENOENT');
+  finished(rs, common.expectsError({
+    code: 'ENOENT'
   }));
 }
 
@@ -119,3 +119,37 @@ const { promisify } = require('util');
   rs.push(null);
   rs.resume();
 }
+
+// Test faulty input values and options.
+{
+  const rs = new Readable({
+    read() {}
+  });
+
+  assert.throws(
+    () => finished(rs, 'foo'),
+    {
+      name: /ERR_INVALID_ARG_TYPE/,
+      message: /callback/
+    }
+  );
+  assert.throws(
+    () => finished(rs, 'foo', () => {}),
+    {
+      name: /ERR_INVALID_ARG_TYPE/,
+      message: /opts/
+    }
+  );
+  assert.throws(
+    () => finished(rs, {}, 'foo'),
+    {
+      name: /ERR_INVALID_ARG_TYPE/,
+      message: /callback/
+    }
+  );
+
+  finished(rs, null, common.mustCall());
+
+  rs.push(null);
+  rs.resume();
+}