Notes from Nicholas Zakas' talk on JavaScript error handling

Talk given on 10/8/08

1. Assume code will fail
2. Log errors back to server
   • sample code:
     function log(sev, msg) { var img = new Image(); img.src = 'log.php?sev=' + encodeURIComponent(sev) + '&msg=' + encodeURIComponent(msg); }//example usage
     try {
     //fn()
     catch (e) {
     log(2, ‘fn() failed: ’ + e.message());
     }
   • Log front-end errors to same place as back-end errors
3. Define error handling
   • Use try-catch
   • Catch block stops exception ‘bubbling’ (my phrasing)
4. Identify error points
5. Throw errors
6. Fatal vs. non-fatal
7. Define debug mode