How can I get a JavaScript stack trace when I throw an exception?
If I throw a JavaScript exception myself (eg, throw "AArrggg" ), how can I get the stack trace (in Firebug or otherwise)? Right now I just get the message.
edit : As many people below have posted, it is possible to get a stack trace for a JavaScript exception but I want to get a stack trace for my exceptions. For example:
function foo() {
bar(2);
}
function bar(n) {
if (n < 2)
throw "Oh no! 'n' is too small!"
bar(n-1);
}
When foo is called, I want to get a stack trace which includes the calls to foo , bar , bar .
A modified version of this snippet may somewhat help:
function stacktrace() {
function st2(f) {
return !f ? [] :
st2(f.caller).concat([f.toString().split('(')[0].substring(9) + '(' + f.arguments.join(',') + ')']);
}
return st2(arguments.callee.caller);
}
EDIT 2 (2017) :
In all modern browsers you can simply call: console.trace(); (MDN Reference)
EDIT 1 (2013):
A better (and simpler) solution as pointed out in the comments on the original question is to use the stack property of an Error object like so:
function stackTrace() {
var err = new Error();
return err.stack;
}
This will generate output like this:
DBX.Utils.stackTrace@http://localhost:49573/assets/js/scripts.js:44
DBX.Console.Debug@http://localhost:49573/assets/js/scripts.js:9
.success@http://localhost:49573/:462
x.Callbacks/c@http://localhost:49573/assets/js/jquery-1.10.2.min.js:4
x.Callbacks/p.fireWith@http://localhost:49573/assets/js/jquery-1.10.2.min.js:4
k@http://localhost:49573/assets/js/jquery-1.10.2.min.js:6
.send/r@http://localhost:49573/assets/js/jquery-1.10.2.min.js:6
Giving the name of the calling function along with the URL, its calling function, and so on.
Note that chromium/chrome (other browsers using V8), and also Firefox do have a convenient interface to get a stacktrace through a stack property on Error objects.
try {
// Code throwing an exception
} catch(e) {
console.log(e.stack);
}
It applies for the base exceptions as well as for the ones you throw yourself. (Considered that you use the Error class, which is anyway a good practice).
See details on V8 documentation
In Firefox it seems that you don't need to throw the exception. It's sufficient to do
e = new Error();
console.log(e.stack);