From 1d5953e8c78bc8ebb2dd91e72c27e503cb3189b0 Mon Sep 17 00:00:00 2001
From: kkapsner <github@mail.kkapsner.de>
Date: Wed, 5 Sep 2018 15:50:59 +0200
Subject: [PATCH] Added protection from undefined properties.

DOMRect has some new properties that are only in nightly at the moment.
---
 lib/intercept.js | 57 +++++++++++++++++++++++++++++-------------------
 1 file changed, 34 insertions(+), 23 deletions(-)

diff --git a/lib/intercept.js b/lib/intercept.js
index e35437e..c5055ef 100644
--- a/lib/intercept.js
+++ b/lib/intercept.js
@@ -100,7 +100,13 @@
 					forEachFunction(function({name, object}){
 						var map = originalPropertyDescriptors[name] || new WeakMap();
 						originalPropertyDescriptors[name] = map;
-						map.set(object, Object.getOwnPropertyDescriptor(object, name));
+						
+						const originalPropertyDescriptor = Object.getOwnPropertyDescriptor(object, name);
+						if (!originalPropertyDescriptor){
+							return;
+						}
+						
+						map.set(object, originalPropertyDescriptor);
 						Object.defineProperty(
 							object,
 							name,
@@ -145,11 +151,14 @@
 				if (preIntercepted){
 					preIntercepted = false;
 					forEachFunction(function({name, object}){
-						Object.defineProperty(
-							object,
-							name,
-							originalPropertyDescriptors[name].get(object)
-						);
+						const originalPropertyDescriptor = originalPropertyDescriptors[name].get(object);
+						if (originalPropertyDescriptor){
+							Object.defineProperty(
+								object,
+								name,
+								originalPropertyDescriptor
+							);
+						}
 					});
 				}
 			};
@@ -286,26 +295,28 @@
 							var original = constructor.prototype[name];
 							const checker = generateChecker(name, changedFunction, siteStatus, original);
 							var descriptor = Object.getOwnPropertyDescriptor(constructor.prototype, name);
-							if (descriptor.hasOwnProperty("value")){
-								if (changedFunction.fakeGenerator){
-									descriptor.value = exportFunction(
-										changedFunction.fakeGenerator(checker),
-										window
-									);
+							if (descriptor){
+								if (descriptor.hasOwnProperty("value")){
+									if (changedFunction.fakeGenerator){
+										descriptor.value = exportFunction(
+											changedFunction.fakeGenerator(checker),
+											window
+										);
+									}
+									else {
+										descriptor.value = null;
+									}
 								}
 								else {
-									descriptor.value = null;
+									descriptor.get = exportFunction(function(){
+										return exportFunction(
+											changedFunction.fakeGenerator(checker),
+											window
+										);
+									}, window);
 								}
+								Object.defineProperty(constructor.prototype, name, descriptor);
 							}
-							else {
-								descriptor.get = exportFunction(function(){
-									return exportFunction(
-										changedFunction.fakeGenerator(checker),
-										window
-									);
-								}, window);
-							}
-							Object.defineProperty(constructor.prototype, name, descriptor);
 						}
 					});
 				}
@@ -319,7 +330,7 @@
 						const object = objectGetter(getWrapped(window));
 						if (object){
 							const descriptor = Object.getOwnPropertyDescriptor(object, name);
-							if (descriptor.hasOwnProperty("get")){
+							if (descriptor && descriptor.hasOwnProperty("get")){
 								var original = descriptor.get;
 								const checker = generateChecker(name, changedGetter, siteStatus, original);
 								const getter = changedGetter.getterGenerator(checker);