From 147ce3e4c36807b5c61c7e82ccfff1490eed54ff Mon Sep 17 00:00:00 2001
From: Jay Phelps <hello@jayphelps.com>
Date: Sat, 5 Nov 2016 14:18:28 -0700
Subject: [PATCH] fix(fromEvent): Throw if event target is invalid (#2107)

---
 .markdown-doctest-setup.js            |  5 ++++-
 spec/observables/fromEvent-spec.ts    | 11 +++++++++++
 src/observable/FromEventObservable.ts |  2 ++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/.markdown-doctest-setup.js b/.markdown-doctest-setup.js
index 075223da95..d532c05291 100644
--- a/.markdown-doctest-setup.js
+++ b/.markdown-doctest-setup.js
@@ -23,7 +23,10 @@ module.exports = {
   globals: {
     document: {
       querySelector: function () {
-        return {addEventListener: function () {}}
+        return {
+          addEventListener: function () {},
+          removeEventListener: function () {}
+        }
       }
     },
     hot: marbleTesting.hot,
diff --git a/spec/observables/fromEvent-spec.ts b/spec/observables/fromEvent-spec.ts
index 4790e24fa1..c608321f53 100644
--- a/spec/observables/fromEvent-spec.ts
+++ b/spec/observables/fromEvent-spec.ts
@@ -115,6 +115,17 @@ describe('Observable.fromEvent', () => {
     expect(offHandler).to.equal(onHandler);
   });
 
+  it('should error on invalid event targets', () => {
+    const obj = {
+      addListener: () => {
+        //noop
+      }
+    };
+
+    const subscribe = () => Observable.fromEvent(<any>obj, 'click').subscribe();
+    expect(subscribe).to.throw(TypeError, 'Invalid event target');
+  });
+
   it('should pass through options to addEventListener', () => {
     let actualOptions;
     const expectedOptions = { capture: true, passive: true };
diff --git a/src/observable/FromEventObservable.ts b/src/observable/FromEventObservable.ts
index edd5942617..1b1bb67bf5 100644
--- a/src/observable/FromEventObservable.ts
+++ b/src/observable/FromEventObservable.ts
@@ -133,6 +133,8 @@ export class FromEventObservable<T> extends Observable<T> {
       const source = sourceObj;
       sourceObj.addListener(eventName, handler);
       unsubscribe = () => source.removeListener(eventName, handler);
+    } else {
+      throw new TypeError('Invalid event target');
     }
 
     subscriber.add(new Subscription(unsubscribe));