Javascript has this great callback window.onerror
. It's quite convenient to track any error. However, it calls with the error name, the file name and the line. It's certainly not as rich as getting the actual error object from a try...catch
statement. The actual error object contains a lot more data, so I am trying to get that. Unfortunately, try...catch
statement do not work fine when you start having async code.
Is there a way to combine and get the best of both worlds? I initially looked for a way to get the last error triggered within an onerror
block, but it looks like JS doesn't store that.
Any clue?
To check if a variable is of type Error , use the instanceof operator - err instanceof Error . The instanceof operator returns true if the prototype property of a constructor appears in the prototype chain of the object. Copied!
onerror is a special browser event that fires whenever an uncaught JavaScript error has been thrown. It's one of the easiest ways to log client-side errors and report them to your servers. It's also one of the major mechanisms by which Sentry's client JavaScript integration (raven-js) works.
The onerror event is triggered if an error occurs while loading an external file (e.g. a document or an image). Tip: When used on audio/video media, related events that occurs when there is some kind of disturbance to the media loading process, are: onabort. onemptied. onstalled.
To return errors from functions as promises, there are generally two ways to produce rejected promises: The reject function of your Promise library. Throwing an exception in a then callback or returning a rejected promise from it will reject the resulting promise.
this is now possible in some browsers. The spec was updated to include the actual error with stacktrace as the 5th parameter.
the problem is that not every browser supports this yet, so you could do something like this:
window.onerror = function(message, filename, lineno, colno, error) { if(error != null) { //handle the error with stacktrace in error.stack } else { //sadly only 'message', 'filename' and 'lineno' work here } };
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With