Exception handling in Chrome extensions

Question

I can't seem to find anything in the Chrome extension documentation about exception handling. All the asynchronous apis makes it very difficult without littering the code with try / catch statements everywhere..

How can I add a global exception handler to my background page that'll allow me to do some resource cleanup in the case of an exception?

Answer 1

You can get the error in the execute script callback with chrome.runtime.lastError:

chrome.tabs.executeScript(tabId, details, function() {
    if (chrome.runtime.lastError) {
       var errorMsg = chrome.runtime.lastError.message
       if (errorMsg == "Cannot access a chrome:// URL") {
           // Error handling here
       }
    }
})

Answer 2

I haven't been able to find a global error handler but I was able to come up with a solution that works just as well.

It does depend on what methods you're calling though. Most of my errors came from calling chrome.tabs.executeScript() on a chrome:// page or a chrome webstore page. The last parameter of this function is a callback that contains a results array. I found that if this was undefined I was getting an error back. This way I was able to set up a simple error handling function to notify the user when there was an error.

chrome.tabs.executeScript(null, {file: '/path/to/file.js'}, function(results) {
    if (results === undefined) {
        // Fire error handling code
    }
});

Again, Idk if this is applicable with the methods that you're calling but I was able to do what I wanted this way.