Scenario:
In the project I am currently involved in, there has been a transition from utilizing AngularJS (1.6.2) with JavaScript to TypeScript 2.1.5.
We had implemented a decorator on the $exceptionHandler service which would trigger a call to a common API upon encountering JavaScript exceptions. This allowed our development team to easily monitor and address front-end errors faced by end-users in real-time.
Challenge:
Recently, I converted this decorator from JavaScript to TypeScript. However, upon running the application, I was met with a blank screen. After thorough debugging, it was evident that the issue stemmed from AngularJS expecting the $provide.decorator method to include a function along with a list of dependencies. Instead, an object was being passed, causing Angular to go into fail-safe mode.
The problem was identified by setting breakpoints within the angular.js file itself, pinpointing the failure at line 4809 inside the
createInternalInjector(cache, factory)invoke(fn, self, locals, serviceName)['$delegate', '$injector'], without the function.
As a workaround, creating a JavaScript function within the class code was considered. However, this approach proved ineffective due to the noImplicitAny setting in our
ts.config</code file and TypeScript's inability to recognize <code>functionExceptionHandler.
Revised TypeScript Exception Handler:
export class ExceptionHandler {
public constructor(
$provide: ng.auto.IProviderService
) {
$provide.decorator('$exceptionHandler`, [
'$delegate',
'$injector',
this.dispatchErrorEmail
]);
}
public dispatchErrorEmail(
$delegate: ng.IExceptionHandlerService,
$injector: ng.auto.IInjectorService
): (exception: any, cause: any) => void {
return (exception: any, cause: any) => {
// Default implementation.
$delegate(exception, cause);
// Inject Web Data Service for handling emails.
let webDataSvc: WebDataSvc = $injector.get<WebDataSvc>('webDataSvc');
// Send email notification to developers.
let args: Object = {
'exception': exception
};
webDataSvc.get('/api/common/errorNotification', args);
};
}
}
angular.module('app').config(['$provide', ExceptionHandler]);
Original JS Version:
(function () {
'use strict';
angular.module('app').config(['$provide', decorateExceptionHandler]);
function decorateExceptionHandler($provide) {
$provide.decorator('$exceptionHandler', ['$delegate', '$injector', dispatchErrorEmail]);
}
function dispatchErrorEmail($delegate, $injector) {
return function (exception, cause) {
// Execute default functionality.
$delegate(exception, cause);
var webDataSvc = $injector.get('webDataSvc');
var args = {
'exception': exception,
};
webDataSvc.get('/api/common/ErrorNotification', args);
};
}
})();
Inquiries:
1. How can the TypeScript Exception Handler be modified to integrate seamlessly with AngularJS?
2. If not feasible, could this be categorized as an AngularJS glitch requiring further attention? Given the widespread use of AngularJS with TypeScript, facing hindrances in service decoration due to language preferences seems like a significant issue.