How to log exceptions in JavaScript

Question

As a C# developer I'm used to the following style of exception handling:

try
{
    throw SomeException("hahahaha!");
}
catch (Exception ex)
{
    Log(ex.ToString());
}

Output
------

SomeNamespace.SomeException: hahahaha!
    at ConsoleApplication1.Main() in ConsoleApplication1Program.cs:line 27

Its really simple, and yet tells me everything I need to know about what the exception was and where it was.

How do I achieve the equivalent thing in JavaScript where the exception object itself might just be a string. I really want to be able to know the exact line of code where the exception happened, however the following code doesn't log anything useful at all:

try
{
    var WshShell = new ActiveXObject("WScript.Shell");
    return WshShell.RegRead("HKEY_LOCAL_MACHINE\Some\Invalid\Location");
}
catch (ex)
{
    Log("Caught exception: " + ex);
}

Output
------

Caught exception: [object Error]

EDIT (again): Just to clarify, this is for internal application that makes heavy use of JavaScript. I'm after a way of extracting useful information from JavaScript errors that may be caught in the production system - I already have a logging mechanism, just want a way of getting a sensible string to log.

question from:https://stackoverflow.com/questions/1238000/how-to-log-exceptions-in-javascript

Answer 1

You don't specify if you are working in the browser or the server. If it's the former, there is a new console.error method and e.stack property:

try {
    // do some crazy stuff
} catch (e) {
    console.error(e, e.stack);
}

Please keep in mind that error will work on Firefox and Chrome, but it's not standard. A quick example that will downgrade to console.log and log e if there is no e.stack:

try {
    // do some crazy stuff
} catch (e) {
    (console.error || console.log).call(console, e.stack || e);
}