preload: use page_params only when it exists.

This PR adds a params-util.js file which checks wheather the
page_params exists or not.

Fixes: #517.

Author: aashish-ak

app/renderer/js/notification/index.js

@@ -4,6 +4,7 @@ const {
   remote: { app }
 } = require('electron');
 
+const params = require('../utils/params-util.js');
 const DefaultNotification = require('./default-notification');
 const { appId, loadBots } = require('./helpers');
 
@@ -19,9 +20,8 @@ if (process.platform === 'darwin') {
 }
 
 window.addEventListener('load', () => {
-	// Call this function only when user is logged in
 	// eslint-disable-next-line no-undef, camelcase
-	if (page_params.realm_uri) {
+	if (params.isPageParams() && page_params.realm_uri) {
 		loadBots();
 	}
 });

app/renderer/js/preload.js

@@ -5,6 +5,7 @@ const SetupSpellChecker = require('./spellchecker');
 
 const ConfigUtil = require(__dirname + '/utils/config-util.js');
 const LinkUtil = require(__dirname + '/utils/link-util.js');
+const params = require(__dirname + '/utils/params-util.js');
 
 // eslint-disable-next-line import/no-unassigned-import
 require('./notification');
@@ -42,46 +43,44 @@ process.once('loaded', () => {
 
 // To prevent failing this script on linux we need to load it after the document loaded
 document.addEventListener('DOMContentLoaded', () => {
+	if (params.isPageParams()) {
 	// Get the default language of the server
-	const serverLanguage = page_params.default_language; // eslint-disable-line no-undef, camelcase
-
-	if (serverLanguage) {
-		// Set spellcheker language
-		ConfigUtil.setConfigItem('spellcheckerLanguage', serverLanguage);
-		// Init spellchecker
-		SetupSpellChecker.init();
-	}
-
-	// redirect users to network troubleshooting page
-	const getRestartButton = document.querySelector('.restart_get_events_button');
-	if (getRestartButton) {
-		getRestartButton.addEventListener('click', () => {
-			ipcRenderer.send('forward-message', 'reload-viewer');
+		const serverLanguage = page_params.default_language; // eslint-disable-line no-undef, camelcase
+		if (serverLanguage) {
+			// Set spellcheker language
+			ConfigUtil.setConfigItem('spellcheckerLanguage', serverLanguage);
+			// Init spellchecker
+			SetupSpellChecker.init();
+		}
+		// redirect users to network troubleshooting page
+		const getRestartButton = document.querySelector('.restart_get_events_button');
+		if (getRestartButton) {
+			getRestartButton.addEventListener('click', () => {
+				ipcRenderer.send('forward-message', 'reload-viewer');
+			});
+		}
+		// Open image attachment link in the lightbox instead of opening in the default browser
+		const { $, lightbox } = window;
+		$('#main_div').on('click', '.message_content p a', function (e) {
+			const url = $(this).attr('href');
+
+			if (LinkUtil.isImage(url)) {
+				const $img = $(this).parent().siblings('.message_inline_image').find('img');
+
+				// prevent the image link from opening in a new page.
+				e.preventDefault();
+				// prevent the message compose dialog from happening.
+				e.stopPropagation();
+
+				// Open image in the default browser if image preview is unavailable
+				if (!$img[0]) {
+					shell.openExternal(window.location.origin + url);
+				}
+				// Open image in lightbox
+				lightbox.open($img);
+			}
 		});
 	}
-
-	// Open image attachment link in the lightbox instead of opening in the default browser
-	const { $, lightbox } = window;
-
-	$('#main_div').on('click', '.message_content p a', function (e) {
-		const url = $(this).attr('href');
-
-		if (LinkUtil.isImage(url)) {
-			const $img = $(this).parent().siblings('.message_inline_image').find('img');
-
-			// prevent the image link from opening in a new page.
-			e.preventDefault();
-			// prevent the message compose dialog from happening.
-			e.stopPropagation();
-
-			// Open image in the default browser if image preview is unavailable
-			if (!$img[0]) {
-				shell.openExternal(window.location.origin + url);
-			}
-			// Open image in lightbox
-			lightbox.open($img);
-		}
-	});
 });
 
 // Clean up spellchecker events after you navigate away from this page;

app/renderer/js/utils/params-util.js

@@ -0,0 +1,15 @@
+// This util function returns the page params if they're present else returns null
+function isPageParams() {
+	let webpageParams = null;
+	try {
+		// eslint-disable-next-line no-undef, camelcase
+		webpageParams = page_params;
+	} catch (err) {
+		webpageParams = null;
+	}
+	return webpageParams;
+}
+
+module.exports = {
+	isPageParams
+};