fix(endWith): wrap args - they are not observables - in of before concatenating (#4735)

* test(endWith): add failing test
* fix(endWith): wrap args in of before concat
* chore(endWith): remove any assertion

Author: cartant

spec/operators/endWith-spec.ts

@@ -20,6 +20,16 @@ describe('endWith operator', () => {
 expectSubscriptions(e1.subscriptions).toBe(e1subs);
 });
 
+it('should append numbers to a cold Observable',()=>{
+constvalues={a: 1,b: 2,c: 3,s: 4};
+conste1=cold('---a--b--c--|',values);
+conste1subs='^ !';
+constexpected='---a--b--c--(s|)';
+
+expectObservable(e1.pipe(endWith(values.s))).toBe(expected,values);
+expectSubscriptions(e1.subscriptions).toBe(e1subs);
+});
+
 it('should end an observable with given value',()=>{
 conste1=hot('--a--|');
 conste1subs='^ !';

src/internal/operators/endWith.ts

@@ -1,5 +1,6 @@
 import{Observable}from'../Observable';
 import{concat}from'../observable/concat';
+import{of}from'../observable/of';
 import{MonoTypeOperatorFunction,SchedulerLike,OperatorFunction}from'../types';
 
 /* tslint:disable:max-line-length */
@@ -62,5 +63,5 @@ export function endWith<T, Z = T>(...array: Array<Z | SchedulerLike>): OperatorF
  * @owner Observable
  */
 exportfunctionendWith<T>(...array: Array<T|SchedulerLike>): MonoTypeOperatorFunction<T>{
-return(source: Observable<T>)=>concat(source, ...(arrayasany[]))asObservable<T>;
+return(source: Observable<T>)=>concat(source,of(...array))asObservable<T>;
 }