Uncaught TypeError: Cannot read property 'toString' of null
below is the code giving the issue:
handler is null.
function patchEventTargetMethods(obj) {
var addDelegate = obj.addEventListener;
obj.addEventListener = function (eventName, handler) {
var fn;
//Ignore special listeners of IE11 & Edge dev tools, see https://github.com/angular/zone.js/issues/150
if (handler.toString() !== "[object FunctionWrapper]") {
Uncaught TypeError: Cannot read property 'toString' of null
below is the code giving the issue: handler is null.
function patchEventTargetMethods(obj) { var addDelegate = obj.addEventListener; obj.addEventListener = function (eventName, handler) { var fn; //Ignore special listeners of IE11 & Edge dev tools, see https://github.com/angular/zone.js/issues/150 if (handler.toString() !== "[object FunctionWrapper]") {