fix(holdSubject): Fix holdSubject to buffer without consumer

In previous 4.x releases, holdSubject buffered events regardless of whether it had a consumer. This
was broken in a recent fix to another issue and should be fixed to be consistent with previous 4.x
releases.

src/HoldSubjectSource.ts

@@ -25,9 +25,12 @@ export class HoldSubjectSource<T> extends BasicSubjectSource<T> {
   }
 
   next (value: T) {
-    if (!this.active || this.scheduler === void 0) { return; }
+    if (this.scheduler === void 0) { return; }
     const time = this.scheduler.now();
     this.buffer = dropAndAppend({time, value}, this.buffer, this.bufferSize);
-    this._next(time, value);
+
+    if (this.active) {
+      this._next(time, value);
+    }
   }
 }

test/holdSubject.js

@@ -9,25 +9,37 @@ describe('holdSubject', () => {
     })
   })
 
-  it('should replay the last value', () => {
+  it('should buffer with consumer and replay last value', () => {
     const stream = holdSubject()
+
+    stream.observe(() => {})
+
     stream.next(1)
     stream.next(2)
 
-    setTimeout(() => stream.complete(), 10)
+    setTimeout(() => stream.complete())
 
-    return stream.forEach(x => {
-      assert.strictEqual(x, 2)
-    })
+    return stream
+      .reduce((x, y) => x.concat(y), [])
+      .then(x => assert.deepEqual(x, [ 2 ]))
+  })
+
+  it('should buffer without consumer and replay last value', () => {
+    const stream = holdSubject()
 
+    stream.next(1)
+    stream.next(2)
+
+    setTimeout(() => stream.complete())
+
+    return stream
+      .reduce((x, y) => x.concat(y), [])
+      .then(x => assert.deepEqual(x, [ 2 ]))
   })
 
   it('should allow for adjusting bufferSize of stream', () => {
     const stream = holdSubject(3)
 
-    // Add an observer so the stream begins buffering events
-    stream.observe(() => {})
-
     stream.next(1)
     stream.next(2)
     stream.next(3)
@@ -40,6 +52,5 @@ describe('holdSubject', () => {
       .then(x => {
         assert.deepEqual(x, [2, 3, 4])
       })
-
   })
 })