fix(debounce): Dispose the source disposable (#472)

* Dispose the source disposable

When disposing a debounce stream we also need to dispose the source disposable

* add a test case for debounce dispose

* drain the debounced stream in the test

* fix(debounce): assign source disposable directly to debounce disposable

Suggested by mostjs/core#107

* fix linting issue

src/combinator/limit.js

@@ -4,7 +4,6 @@
 
 import Stream from '../Stream'
 import Pipe from '../sink/Pipe'
-import * as dispose from '../disposable/dispose'
 import PropagateTask from '../scheduler/PropagateTask'
 import Map from '../fusion/Map'
 
@@ -84,9 +83,7 @@ function DebounceSink (dt, source, sink, scheduler) {
   this.scheduler = scheduler
   this.value = void 0
   this.timer = null
-
-  var sourceDisposable = source.run(this, scheduler)
-  this.disposable = dispose.all([this, sourceDisposable])
+  this.disposable = source.run(this, scheduler)
 }
 
 DebounceSink.prototype.event = function (t, x) {
@@ -110,6 +107,7 @@ DebounceSink.prototype.error = function (t, x) {
 
 DebounceSink.prototype.dispose = function () {
   this._clearTimer()
+  return this.disposable.dispose()
 }
 
 DebounceSink.prototype._clearTimer = function () {

test/limit-test.js

@@ -10,6 +10,9 @@ var take = require('../src/combinator/slice').take
 var fromArray = require('../src/source/fromArray').fromArray
 var core = require('../src/source/core')
 var Map = require('../src/fusion/Map').default
+var drain = require('../src/combinator/observe').drain
+var Stream = require('../src/Stream').default
+var FakeDisposeSource = require('./helper/FakeDisposeSource')
 
 var empty = core.empty
 var streamOf = core.of
@@ -95,6 +98,16 @@ describe('debounce', function () {
         ])
       })
   })
+
+  it('should dispose', function () {
+    var dispose = this.spy()
+    var s = new Stream(new FakeDisposeSource(dispose, streamOf(sentinel).source))
+    var debounced = limit.debounce(1, s)
+
+    return drain(debounced).then(function () {
+      expect(dispose).toHaveBeenCalledOnce()
+    })
+  })
 })
 
 describe('throttle', function () {