From 915a2a84cbc0342f0d011ae8373065cc034b2371 Mon Sep 17 00:00:00 2001
From: Mateusz Podlasin <Podlas29@gmail.com>
Date: Sun, 5 Feb 2017 13:26:37 +0100
Subject: [PATCH] fix(bindCallback): emit undefined when callback is without
 arguments

In resulting Observable emit undefined when callback is called without
parameters, instead of emitting empty array.
---
 spec/observables/bindCallback-spec.ts     | 36 +++++++++++++++++++++++
 src/observable/BoundCallbackObservable.ts |  5 ++--
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/spec/observables/bindCallback-spec.ts b/spec/observables/bindCallback-spec.ts
index cae44820a0..59c92ab1e0 100644
--- a/spec/observables/bindCallback-spec.ts
+++ b/spec/observables/bindCallback-spec.ts
@@ -8,6 +8,23 @@ const Observable = Rx.Observable;
 /** @test {bindCallback} */
 describe('Observable.bindCallback', () => {
   describe('when not scheduled', () => {
+    it('should emit undefined from a callback without arguments', () => {
+      function callback(cb) {
+        cb();
+      }
+      const boundCallback = Observable.bindCallback(callback);
+      const results = [];
+
+      boundCallback()
+        .subscribe((x: any) => {
+          results.push(typeof x);
+        }, null, () => {
+          results.push('done');
+        });
+
+      expect(results).to.deep.equal(['undefined', 'done']);
+    });
+
     it('should emit one value from a callback', () => {
       function callback(datum, cb) {
         cb(datum);
@@ -104,6 +121,25 @@ describe('Observable.bindCallback', () => {
   });
 
   describe('when scheduled', () => {
+    it('should emit undefined from a callback without arguments', () => {
+      function callback(cb) {
+        cb();
+      }
+      const boundCallback = Observable.bindCallback(callback, null, rxTestScheduler);
+      const results = [];
+
+      boundCallback()
+        .subscribe((x: any) => {
+          results.push(typeof x);
+        }, null, () => {
+          results.push('done');
+        });
+
+      rxTestScheduler.flush();
+
+      expect(results).to.deep.equal(['undefined', 'done']);
+    });
+
     it('should emit one value from a callback', () => {
       function callback(datum, cb) {
         cb(datum);
diff --git a/src/observable/BoundCallbackObservable.ts b/src/observable/BoundCallbackObservable.ts
index bdcc87a178..dcc95cac5e 100644
--- a/src/observable/BoundCallbackObservable.ts
+++ b/src/observable/BoundCallbackObservable.ts
@@ -15,6 +15,7 @@ export class BoundCallbackObservable<T> extends Observable<T> {
   subject: AsyncSubject<T>;
 
   /* tslint:disable:max-line-length */
+  static create(callbackFunc: (callback: () => any) => any, selector?: void, scheduler?: IScheduler): () => Observable<void>;
   static create<R>(callbackFunc: (callback: (result: R) => any) => any, selector?: void, scheduler?: IScheduler): () => Observable<R>;
   static create<T, R>(callbackFunc: (v1: T, callback: (result: R) => any) => any, selector?: void, scheduler?: IScheduler): (v1: T) => Observable<R>;
   static create<T, T2, R>(callbackFunc: (v1: T, v2: T2, callback: (result: R) => any) => any, selector?: void, scheduler?: IScheduler): (v1: T, v2: T2) => Observable<R>;
@@ -119,7 +120,7 @@ export class BoundCallbackObservable<T> extends Observable<T> {
               subject.complete();
             }
           } else {
-            subject.next(innerArgs.length === 1 ? innerArgs[0] : innerArgs);
+            subject.next(innerArgs.length <= 1 ? innerArgs[0] : innerArgs);
             subject.complete();
           }
         };
@@ -157,7 +158,7 @@ export class BoundCallbackObservable<T> extends Observable<T> {
             self.add(scheduler.schedule(dispatchNext, 0, { value: result, subject }));
           }
         } else {
-          const value = innerArgs.length === 1 ? innerArgs[0] : innerArgs;
+          const value = innerArgs.length <= 1 ? innerArgs[0] : innerArgs;
           self.add(scheduler.schedule(dispatchNext, 0, { value, subject }));
         }
       };