I got "Uncaught SyntaxError: Invalid or unexpected token" error.
And try to catch with 'try ~ catch' but it's not working.
function a(){
try{
var img1 = "==""; <#-- it occurs error -->
}catch (e) {
console.log("image error:" + e.message);
}
}
You have a syntax error and you can not catch a syntax error.
This error is checked at the parsing or validation time of your code. The try .. catch statement is executed at the running time. And because of this it was not functioning.
If you eval or parse (for ex. JSON) your code you can handle syntax errors only. Or you can create a syntax error like this:
try {
throw new SyntaxError('Hello', 'someFile.js', 18);
} catch (e) {
console.log(e.message); // "Hello"
console.log(e.name); // "SyntaxError"
}
For the eval handled or by self created syntax errors:
A SyntaxError is thrown when the JavaScript engine encounters tokens or token order that does not conform to the syntax of the language when parsing code.
From MDN
Try this:
function a(){
try{
var img1 = "==\"";
//but you have to put some error here without parsing or validation error of your code.
}catch (e) {
console.log("image error:" + e.message);
}
}
I would like to recommend you read:
try...catch Statement
Exception Handling State
Syntax Error
Related
Here is the command that is broken:
fs.writeFileSync('Metadata.json', metadataString);
console.log("Metadata written.");
I have placed a breakpoint and verified that metadataString is actually a string. The console logs Metadata written just fine and the file stays empty...
Not sure what else I can check... Thanks in advance.
fs.writeFileSync() throws an Error exception if it fails. Use a try/catch block:
try {
fs.writeFileSync('Metadata.json', metadataString);
} catch (err) {
console.log('Error writing Metadata.json:' + err.message)
}
I have triggering an Ajax call and in the error callback I am trying to access the exception message(Not the Response Text). I am throwing an exception like this:
throw new Exception("Please enter a response")
Now I want to get the above message and display it in alert box.
I searched stackoverflow and found this:
error: function(e,status){
var err = eval("(" + e.responseText + ")");
alert(err.Message);
}
but the above doesn't work.
I am getting the response text but not able to access that particular message.
The error that I am getting is Uncaught SyntaxError: Unexpected token <
When your server throws an Internal Server Error, from Javascript side it's still a succes. how about adding the Status code response instead of throwing exception from the backend
return new HttpStatusCodeResult(400, "Custom Error Message 2");
You can refer this and try to get error message as alert(err.message); (lowercase) not alert(err.Message);
Does anybody know how to print more details about unexpected error that occurred?
I have this piece of code:
process.on('uncaughtException', function(err)
{
console.log("Unexpected error occurred. " + err + ".");
process.exit(1);
});
...and when error occurs this is printed: "Unexpected error occurred. Error: connect ECONNREFUSED."
There is no details about this error. Like what exactly failed, which connection, ip:port. How can I fetch that kind of data? And I don't want to use Domain module (in case somebody suggests).
I am using .net modular and opening tcp port on 6112.
var net = require('net');
var server = net.createServer(function (socket) { //'connection' listener
});
server.listen(6112, function () { //'listening' listener
console.log('server started');
});
On the same machine i start a java socket in main.
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
System.out.println("Connecting...");
Socket socket = new Socket("localhost", 6112);
System.out.println("Connected");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
I get this exception,
C:\Users\Mustafa\WebstormProjects\Node.Js>node hello.js
server started
events.js:72
throw er; // Unhandled 'error' event
^
Error: read ECONNRESET
at errnoException (net.js:884:11)
at TCP.onread (net.js:539:19)
Is this like a bug or something, cause if once i get through this bug, I will be good thanks.
I haven't used the debugger cause as Ryan said it him self a year ago that it is still shitt.
You need to listen for errors on the socket. Node has the default behavior that when something does .emit('error'), if there are no error handlers attached, it will throw the error instead, thus crashing the application.
var server = net.createServer(function (socket) {
socket.on('error', function(err){
// Handle the connection error.
});
});
You are creating a socket and connecting from it, but not closing it. So when the program finishes, to node.js it looks like connection is reset (closed abruptly). Call socket.close(); before program finishes.
You can structure your code in this way :
try {
tryStatements //your code that is causing exceptions
}
catch(exception){
catchStatements //handle caught exceptions
}
finally {
finallyStatements //execute it anyways
}
Or if you like to catch uncaught exceptions from runtime, use this (main process won't exit on exceptions)
process.on('uncaughtException', function(err) {
console.log('Caught exception: ' + err);
console.log(err.stack);
});
The problem is in java code which is causing node.js to exit on exception. So be sure to add socket.close();. Above is just error handling on node.js part.
I want to catch a specific failure of this JavaScript code:
var script = $wnd.document.createElement('script');
script.setAttribute('src', url);
script.setAttribute('type', 'text/javascript');
When the url where the script resides needs the user to be logged in, and so returns an HTTP 401 Unauthorized error.
None of the values I understand that error (in a try/catch) can take on seem to match very well.
EvalError: An error in the eval() function has occurred.
RangeError: Out of range number value has occurred.
ReferenceError: An illegal reference has occurred.
SyntaxError: A syntax error within code inside the eval() function has occurred. event.
TypeError: An error in the expected variable type has occurred.
URIError: An error when encoding or decoding the URI has occurred (ie: when calling encodeURI()).
Is there any way to catch specifically this 401 error, or at least the class of IO error that would be thrown by not being able to load the script.
Thanks
script.addEventListener('error', function(){
// Didn't load
}, true);