test: cleanup stream tests

const and let instead var
assert.strictEqual instead assert.equal

PR-URL: #8668
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-stream-big-packet.js

@@ -1,10 +1,10 @@
 'use strict';
 require('../common');
-var assert = require('assert');
-var util = require('util');
-var stream = require('stream');
+const assert = require('assert');
+const util = require('util');
+const stream = require('stream');
 
-var passed = false;
+let passed = false;
 
 function PassThrough() {
   stream.Transform.call(this);
@@ -27,15 +27,15 @@ TestStream.prototype._transform = function(chunk, encoding, done) {
   done();
 };
 
-var s1 = new PassThrough();
-var s2 = new PassThrough();
-var s3 = new TestStream();
+const s1 = new PassThrough();
+const s2 = new PassThrough();
+const s3 = new TestStream();
 s1.pipe(s3);
 // Don't let s2 auto close which may close s3
 s2.pipe(s3, {end: false});
 
 // We must write a buffer larger than highWaterMark
-var big = Buffer.alloc(s1._writableState.highWaterMark + 1, 'x');
+const big = Buffer.alloc(s1._writableState.highWaterMark + 1, 'x');
 
 // Since big is larger than highWaterMark, it will be buffered internally.
 assert(!s1.write(big));

test/parallel/test-stream-big-push.js

@@ -1,17 +1,17 @@
 'use strict';
 require('../common');
-var assert = require('assert');
-var stream = require('stream');
-var str = 'asdfasdfasdfasdfasdf';
+const assert = require('assert');
+const stream = require('stream');
+const str = 'asdfasdfasdfasdfasdf';
 
-var r = new stream.Readable({
+const r = new stream.Readable({
   highWaterMark: 5,
   encoding: 'utf8'
 });
 
-var reads = 0;
-var eofed = false;
-var ended = false;
+let reads = 0;
+let eofed = false;
+let ended = false;
 
 r._read = function(n) {
   if (reads === 0) {
@@ -21,7 +21,7 @@ r._read = function(n) {
     reads++;
   } else if (reads === 1) {
     var ret = r.push(str);
-    assert.equal(ret, false);
+    assert.strictEqual(ret, false);
     reads++;
   } else {
     assert(!eofed);
@@ -40,25 +40,25 @@ var ret = r.push(str);
 // should be false.  > hwm
 assert(!ret);
 var chunk = r.read();
-assert.equal(chunk, str);
+assert.strictEqual(chunk, str);
 chunk = r.read();
-assert.equal(chunk, null);
+assert.strictEqual(chunk, null);
 
 r.once('readable', function() {
   // this time, we'll get *all* the remaining data, because
   // it's been added synchronously, as the read WOULD take
   // us below the hwm, and so it triggered a _read() again,
   // which synchronously added more, which we then return.
   chunk = r.read();
-  assert.equal(chunk, str + str);
+  assert.strictEqual(chunk, str + str);
 
   chunk = r.read();
-  assert.equal(chunk, null);
+  assert.strictEqual(chunk, null);
 });
 
 process.on('exit', function() {
   assert(eofed);
   assert(ended);
-  assert.equal(reads, 2);
+  assert.strictEqual(reads, 2);
   console.log('ok');
 });

test/parallel/test-stream-duplex.js

@@ -1,16 +1,15 @@
 'use strict';
 require('../common');
-var assert = require('assert');
+const assert = require('assert');
+const Duplex = require('stream').Transform;
 
-var Duplex = require('stream').Transform;
-
-var stream = new Duplex({ objectMode: true });
+const stream = new Duplex({ objectMode: true });
 
 assert(stream._readableState.objectMode);
 assert(stream._writableState.objectMode);
 
-var written;
-var read;
+let written;
+let read;
 
 stream._write = function(obj, _, cb) {
   written = obj;

test/parallel/test-stream-end-paused.js

@@ -1,12 +1,12 @@
 'use strict';
 const common = require('../common');
-var assert = require('assert');
+const assert = require('assert');
 
 // Make sure we don't miss the end event for paused 0-length streams
 
-var Readable = require('stream').Readable;
-var stream = new Readable();
-var calledRead = false;
+const Readable = require('stream').Readable;
+const stream = new Readable();
+let calledRead = false;
 stream._read = function() {
   assert(!calledRead);
   calledRead = true;

test/parallel/test-stream-ispaused.js

@@ -1,10 +1,9 @@
 'use strict';
 require('../common');
-var assert = require('assert');
+const assert = require('assert');
+const stream = require('stream');
 
-var stream = require('stream');
-
-var readable = new stream.Readable();
+const readable = new stream.Readable();
 
 // _read is a noop, here.
 readable._read = Function();

test/parallel/test-stream-pipe-after-end.js

@@ -1,10 +1,9 @@
 'use strict';
 require('../common');
-var assert = require('assert');
-
-var Readable = require('_stream_readable');
-var Writable = require('_stream_writable');
-var util = require('util');
+const assert = require('assert');
+const Readable = require('_stream_readable');
+const Writable = require('_stream_writable');
+const util = require('util');
 
 util.inherits(TestReadable, Readable);
 function TestReadable(opt) {
@@ -35,11 +34,11 @@ TestWritable.prototype._write = function(chunk, encoding, cb) {
 };
 
 // this one should not emit 'end' until we read() from it later.
-var ender = new TestReadable();
-var enderEnded = false;
+const ender = new TestReadable();
+let enderEnded = false;
 
 // what happens when you pipe() a Readable that's already ended?
-var piper = new TestReadable();
+const piper = new TestReadable();
 // pushes EOF null, and length=0, so this will trigger 'end'
 piper.read();
 
@@ -48,11 +47,11 @@ setTimeout(function() {
     enderEnded = true;
   });
   assert(!enderEnded);
-  var c = ender.read();
+  const c = ender.read();
   assert.equal(c, null);
 
-  var w = new TestWritable();
-  var writableFinished = false;
+  const w = new TestWritable();
+  let writableFinished = false;
   w.on('finish', function() {
     writableFinished = true;
   });

test/parallel/test-stream-pipe-cleanup.js

@@ -1,11 +1,10 @@
 'use strict';
 // This test asserts that Stream.prototype.pipe does not leave listeners
 // hanging on the source or dest.
-
 require('../common');
-var stream = require('stream');
-var assert = require('assert');
-var util = require('util');
+const stream = require('stream');
+const assert = require('assert');
+const util = require('util');
 
 function Writable() {
   this.writable = true;
@@ -33,20 +32,20 @@ function Duplex() {
 }
 util.inherits(Duplex, Writable);
 
-var i = 0;
-var limit = 100;
+let i = 0;
+const limit = 100;
 
-var w = new Writable();
+let w = new Writable();
 
-var r;
+let r;
 
 for (i = 0; i < limit; i++) {
   r = new Readable();
   r.pipe(w);
   r.emit('end');
 }
-assert.equal(0, r.listeners('end').length);
-assert.equal(limit, w.endCalls);
+assert.strictEqual(0, r.listeners('end').length);
+assert.strictEqual(limit, w.endCalls);
 
 w.endCalls = 0;
 
@@ -55,8 +54,8 @@ for (i = 0; i < limit; i++) {
   r.pipe(w);
   r.emit('close');
 }
-assert.equal(0, r.listeners('close').length);
-assert.equal(limit, w.endCalls);
+assert.strictEqual(0, r.listeners('close').length);
+assert.strictEqual(limit, w.endCalls);
 
 w.endCalls = 0;
 
@@ -67,36 +66,37 @@ for (i = 0; i < limit; i++) {
   r.pipe(w);
   w.emit('close');
 }
-assert.equal(0, w.listeners('close').length);
+assert.strictEqual(0, w.listeners('close').length);
 
 r = new Readable();
 w = new Writable();
-var d = new Duplex();
+const d = new Duplex();
 r.pipe(d); // pipeline A
 d.pipe(w); // pipeline B
-assert.equal(r.listeners('end').length, 2);   // A.onend, A.cleanup
-assert.equal(r.listeners('close').length, 2); // A.onclose, A.cleanup
-assert.equal(d.listeners('end').length, 2);   // B.onend, B.cleanup
-assert.equal(d.listeners('close').length, 3); // A.cleanup, B.onclose, B.cleanup
-assert.equal(w.listeners('end').length, 0);
-assert.equal(w.listeners('close').length, 1); // B.cleanup
+assert.strictEqual(r.listeners('end').length, 2);   // A.onend, A.cleanup
+assert.strictEqual(r.listeners('close').length, 2); // A.onclose, A.cleanup
+assert.strictEqual(d.listeners('end').length, 2);   // B.onend, B.cleanup
+// A.cleanup, B.onclose, B.cleanup
+assert.strictEqual(d.listeners('close').length, 3);
+assert.strictEqual(w.listeners('end').length, 0);
+assert.strictEqual(w.listeners('close').length, 1); // B.cleanup
 
 r.emit('end');
-assert.equal(d.endCalls, 1);
-assert.equal(w.endCalls, 0);
-assert.equal(r.listeners('end').length, 0);
-assert.equal(r.listeners('close').length, 0);
-assert.equal(d.listeners('end').length, 2);   // B.onend, B.cleanup
-assert.equal(d.listeners('close').length, 2); // B.onclose, B.cleanup
-assert.equal(w.listeners('end').length, 0);
-assert.equal(w.listeners('close').length, 1); // B.cleanup
+assert.strictEqual(d.endCalls, 1);
+assert.strictEqual(w.endCalls, 0);
+assert.strictEqual(r.listeners('end').length, 0);
+assert.strictEqual(r.listeners('close').length, 0);
+assert.strictEqual(d.listeners('end').length, 2);   // B.onend, B.cleanup
+assert.strictEqual(d.listeners('close').length, 2); // B.onclose, B.cleanup
+assert.strictEqual(w.listeners('end').length, 0);
+assert.strictEqual(w.listeners('close').length, 1); // B.cleanup
 
 d.emit('end');
-assert.equal(d.endCalls, 1);
-assert.equal(w.endCalls, 1);
-assert.equal(r.listeners('end').length, 0);
-assert.equal(r.listeners('close').length, 0);
-assert.equal(d.listeners('end').length, 0);
-assert.equal(d.listeners('close').length, 0);
-assert.equal(w.listeners('end').length, 0);
-assert.equal(w.listeners('close').length, 0);
+assert.strictEqual(d.endCalls, 1);
+assert.strictEqual(w.endCalls, 1);
+assert.strictEqual(r.listeners('end').length, 0);
+assert.strictEqual(r.listeners('close').length, 0);
+assert.strictEqual(d.listeners('end').length, 0);
+assert.strictEqual(d.listeners('close').length, 0);
+assert.strictEqual(w.listeners('end').length, 0);
+assert.strictEqual(w.listeners('close').length, 0);