Sonarr/src/UI/Instrumentation/ErrorHandler.js

define(
    [
        'jquery',
        'messenger'
    ], function ($, Messenger) {
        'use strict';

        window.alert = function (message) {
            new Messenger().post(message);
        };

        var addError = function (message) {
            $('#errors').append('<div>' + message + '</div>');
        };

        window.onerror = function (msg, url, line) {

            try {

                var a = document.createElement('a');
                a.href = url;
                var filename = a.pathname.split('/').pop();

                //Suppress Firefox debug errors when console window is closed
                if (filename.toLowerCase() === 'markupview.jsm' || filename.toLowerCase() === 'markup-view.js') {
                    return false;
                }

                var messageText = filename + ' : ' + line + '</br>' + msg;

                var message = {
                    message        : messageText,
                    type           : 'error',
                    hideAfter      : 1000,
                    showCloseButton: true
                };

                new Messenger().post(message);

                addError(message.message);

            }
            catch (error) {
                console.log('An error occurred while reporting error. ' + error);
                console.log(msg);
                new Messenger().post('Couldn\'t report JS error.  ' + msg);
            }

            return false; //don't suppress default alerts and logs.
        };

        $(document).ajaxError(function (event, xmlHttpRequest, ajaxOptions) {

            //don't report 200 error codes
            if (xmlHttpRequest.status >= 200 && xmlHttpRequest.status <= 300) {
                return undefined;
            }

            //don't report aborted requests
            if (xmlHttpRequest.statusText === 'abort') {
                return undefined;
            }

            var message = {
                type           : 'error',
                hideAfter      : 1000,
                showCloseButton: true
            };

            if (xmlHttpRequest.status === 0 && xmlHttpRequest.readyState === 0) {
                return false;
            }

            if (xmlHttpRequest.status === 400 && ajaxOptions.isValidatedCall) {
                return false;
            }

            if (xmlHttpRequest.status === 503) {
                message.message = xmlHttpRequest.responseJSON.message;
            }

            else {
                message.message = '[{0}] {1} : {2}'.format(ajaxOptions.type, xmlHttpRequest.statusText, ajaxOptions.url);
            }

            new Messenger().post(message);
            addError(message.message);

            return false;
        });
    });