Fix SignalR JS client error handling code snippet line numbers (#17834)

* Fix SignalR JS client error handling code snippet line numbers

* more edits

* Simplify

Author: scottaddie

aspnetcore/signalr/javascript-client.md

@@ -138,9 +138,9 @@ SignalR determines which client method to call by matching the method name and a
 
 Chain a `catch` method to the end of the `start` method to handle client-side errors. Use `console.error` to output errors to the browser's console.
 
-[!code-javascript[Error handling](javascript-client/sample/wwwroot/js/chat.js?range=49-51)]
+[!code-javascript[Error handling](javascript-client/sample/wwwroot/js/chat.js?range=50)]
 
-Setup client-side log tracing by passing a logger and type of event to log when the connection is made. Messages are logged with the specified log level and higher. Available log levels are as follows:
+Set up client-side log tracing by passing a logger and type of event to log when the connection is made. Messages are logged with the specified log level and higher. Available log levels are as follows:
 
 * `signalR.LogLevel.Error` – Error messages. Logs `Error` messages only.
 * `signalR.LogLevel.Warning` – Warning messages about potential errors. Logs `Warning`, and `Error` messages.
@@ -171,7 +171,7 @@ Without any parameters, `withAutomaticReconnect()` configures the client to wait
 Before starting any reconnect attempts, the `HubConnection` will transition to the `HubConnectionState.Reconnecting` state and fire its `onreconnecting` callbacks instead of transitioning to the `Disconnected` state and triggering its `onclose` callbacks like a `HubConnection` without automatic reconnect configured. This provides an opportunity to warn users that the connection has been lost and to disable UI elements.
 
 ```javascript
-connection.onreconnecting((error) => {
+connection.onreconnecting(error => {
     console.assert(connection.state === signalR.HubConnectionState.Reconnecting);
 
     document.getElementById("messageInput").disabled = true;
@@ -190,7 +190,7 @@ Since the connection looks entirely new to the server, a new `connectionId` will
 > The `onreconnected` callback's `connectionId` parameter will be undefined if the `HubConnection` was configured to [skip negotiation](xref:signalr/configuration#configure-client-options).
 
 ```javascript
-connection.onreconnected((connectionId) => {
+connection.onreconnected(connectionId => {
     console.assert(connection.state === signalR.HubConnectionState.Connected);
 
     document.getElementById("messageInput").disabled = false;
@@ -220,7 +220,7 @@ async function start() {
 If the client doesn't successfully reconnect within its first four attempts, the `HubConnection` will transition to the `Disconnected` state and fire its [onclose](/javascript/api/%40aspnet/signalr/hubconnection#onclose) callbacks. This provides an opportunity to inform users the connection has been permanently lost and recommend refreshing the page:
 
 ```javascript
-connection.onclose((error) => {
+connection.onclose(error => {
     console.assert(connection.state === signalR.HubConnectionState.Disconnected);
 
     document.getElementById("messageInput").disabled = true;

aspnetcore/signalr/javascript-client/sample/wwwroot/js/chat.js

@@ -4,15 +4,15 @@
 // such as Internet Explorer 11, use a transpiler such as 
 // Babel at http://babeljs.io/. 
 //
-// See Es5-chat.js for a Babel transpiled version of the following code:
+// See Es5-chat.js for a Babel-transpiled version of the following code:
 
 const connection = new signalR.HubConnectionBuilder()
     .withUrl("/chatHub")
     .configureLogging(signalR.LogLevel.Information)
     .build();
 
 connection.on("ReceiveMessage", (user, message) => {
-    const encodedMsg = user + " says " + message;
+    const encodedMsg = `${user} says ${message}`;
     const li = document.createElement("li");
     li.textContent = encodedMsg;
     document.getElementById("messagesList").appendChild(li);
@@ -21,7 +21,7 @@ connection.on("ReceiveMessage", (user, message) => {
 document.getElementById("sendButton").addEventListener("click", event => {
     const user = document.getElementById("userInput").value;
     const message = document.getElementById("messageInput").value;
-    connection.invoke("SendMessage", user, message).catch(err => console.error(err.toString()));
+    connection.invoke("SendMessage", user, message).catch(err => console.error(err));
     event.preventDefault();
 });
 
@@ -43,13 +43,9 @@ connection.onclose(async () => {
 start();
 
 /* this is here to show an alternative to start, with a then
-connection.start().then(function () {
-    console.log("connected");
-});
+connection.start().then(() => console.log("connected"));
 */
 
 /* this is here to show another alternative to start, with a catch
-connection.start().catch(function (err) {
-    return console.error(err.toString());
-});
+connection.start().catch(err => console.error(err));
 */

aspnetcore/signalr/javascript-client/sample/wwwroot/js/es5-chat.js

@@ -19,5 +19,5 @@ document.getElementById("sendButton").addEventListener("click", function (event)
 });
 
 connection.start().catch(function (err) {
-    return console.error(err.toString());
+    return console.error(err);
 });