stream: use more explicit statements

doc/api/errors.md

@@ -829,10 +829,11 @@ Node.js does not allow `stdout` or `stderr` Streams to be closed by user code.
 Used when an attempt is made to close the `process.stdout` stream. By design,
 Node.js does not allow `stdout` or `stderr` Streams to be closed by user code.
 
-<a id="ERR_STREAM_HAS_STRINGDECODER"></a>
-### ERR_STREAM_HAS_STRINGDECODER
+<a id="ERR_STREAM_WRAP"></a>
+### ERR_STREAM_WRAP
 
-Used to prevent an abort if a string decoder was set on the Socket.
+Used to prevent an abort if a string decoder was set on the Socket or if in
+`objectMode`.
 
 Example
 ```js

lib/_stream_transform.js

@@ -76,7 +76,7 @@ function afterTransform(er, data) {
 
   var cb = ts.writecb;
 
-  if (!cb) {
+  if (cb === null) {
     return this.emit('error', new errors.Error('ERR_MULTIPLE_CALLBACK'));
   }
 

lib/_stream_wrap.js

@@ -4,9 +4,6 @@ const assert = require('assert');
 const util = require('util');
 const Socket = require('net').Socket;
 const JSStream = process.binding('js_stream').JSStream;
-// TODO(bmeurer): Change this back to const once hole checks are
-// properly optimized away early in Ignition+TurboFan.
-var Buffer = require('buffer').Buffer;
 const uv = process.binding('uv');
 const debug = util.debuglog('stream_wrap');
 const errors = require('internal/errors');
@@ -47,12 +44,12 @@ function StreamWrap(stream) {
     self.emit('error', err);
   });
   this.stream.on('data', function ondata(chunk) {
-    if (!(chunk instanceof Buffer)) {
+    if (typeof chunk === 'string' || this._readableState.objectMode === true) {
       // Make sure that no further `data` events will happen
       this.pause();
       this.removeListener('data', ondata);
 
-      self.emit('error', new errors.Error('ERR_STREAM_HAS_STRINGDECODER'));
+      self.emit('error', new errors.Error('ERR_STREAM_WRAP'));
       return;
     }
 

lib/internal/errors.js

@@ -171,7 +171,7 @@ E('ERR_SOCKET_BAD_PORT', 'Port should be > 0 and < 65536');
 E('ERR_SOCKET_DGRAM_NOT_RUNNING', 'Not running');
 E('ERR_STDERR_CLOSE', 'process.stderr cannot be closed');
 E('ERR_STDOUT_CLOSE', 'process.stdout cannot be closed');
-E('ERR_STREAM_HAS_STRINGDECODER', 'Stream has StringDecoder');
+E('ERR_STREAM_WRAP', 'Stream has StringDecoder set or is in objectMode');
 E('ERR_TRANSFORM_ALREADY_TRANSFORMING',
   'Calling transform done when still transforming');
 E('ERR_TRANSFORM_WITH_LENGTH_0',

test/parallel/test-stream-wrap-encoding.js

@@ -1,23 +1,42 @@
 'use strict';
 const common = require('../common');
-const assert = require('assert');
 
 const StreamWrap = require('_stream_wrap');
 const Duplex = require('stream').Duplex;
 
-const stream = new Duplex({
-  read: function() {
-  },
-  write: function() {
-  }
-});
+{
+  const stream = new Duplex({
+    read() {},
+    write() {}
+  });
 
-stream.setEncoding('ascii');
+  stream.setEncoding('ascii');
 
-const wrap = new StreamWrap(stream);
+  const wrap = new StreamWrap(stream);
 
-wrap.on('error', common.mustCall(function(err) {
-  assert(/StringDecoder/.test(err.message));
-}));
+  wrap.on('error', common.expectsError({
+    type: Error,
+    code: 'ERR_STREAM_WRAP',
+    message: 'Stream has StringDecoder set or is in objectMode'
+  }));
 
-stream.push('ohai');
+  stream.push('ohai');
+}
+
+{
+  const stream = new Duplex({
+    read() {},
+    write() {},
+    objectMode: true
+  });
+
+  const wrap = new StreamWrap(stream);
+
+  wrap.on('error', common.expectsError({
+    type: Error,
+    code: 'ERR_STREAM_WRAP',
+    message: 'Stream has StringDecoder set or is in objectMode'
+  }));
+
+  stream.push(new Error('foo'));
+}