Question

Now I use this code to save error log from user to database

window.onerror = function (msg, url, line) {
    $.ajax({
        type: "POST",
        url: "call/savelog.php",
        data: {
            type : "bug\n" + version,
            message : 'Error message: '+msg+'\nURL: '+url+'\nLine Number: '+line
        }
    });
    return true;
};

when error occur on jquery or kineticjs function

if it was in javascript console I will got something like this

Uncaught TypeError: Cannot read property '_id' of undefined kinetic-v4.0.2.js:1386
Kinetic.Node.remove kinetic-v4.0.2.js:1386
Kinetic.Layer.remove kinetic-v4.0.2.js:3667
drawCountdown side_play.js:105

so I’ll know error cause by my drawCountdown function in my javascript file side_play.js
but it appear like this in my error log

Error message: Uncaught TypeError: Cannot read property '_id' of undefined
URL: https://myurl.com/js/kinetic-v4.0.2.js
Line Number: 1386 

so I don’t know which function that cause the error.
how to track down to the deepest function that cause error and save error log to database

Answer 1

You can wrap your functions in try/catch statements and if an error occurs you can catch errors and then write them in file via server for example.

try {
  yourFunctionCallHere();
} catch (err) {
   var message = 'yourFunctionCallHere failed: ' + err.message;
   //now you can do smth with this error message, for example send an ajax request to the server...
}