Question

Using SpiderMonkey you can utilize conditional catch blocks to route exceptions to the appropriate handler.

try {
// function could throw three exceptions
getCustInfo("Lee", 1234, "[e-mail]")
}
catch (e if e == "InvalidNameException") {
// call handler for invalid names
bad_name_handler(e)
}
catch (e if e == "InvalidIdException") {
// call handler for invalid ids
bad_id_handler(e)
}
catch (e if e == "InvalidEmailException") {
// call handler for invalid email addresses
bad_email_handler(e)
}
catch (e){
// don't know what to do, but log it
logError(e)
}

example from MDN

However in V8 this code wont compile, any suggestions, or work arounds other than the obvious.

Answer 1

There’s no similar feature in the other JavaScript engines as far as I know.

But it is easy to convert code using this feature:

try {
    A
} catch (e if B) {
    C
}

into code that just uses standard features that all the JavaScript engines support:

try {
    A
} catch (e) {
    if (B) {
        C
    } else {
        throw e;
    }
}

The example you gave is even easier to translate:

try {
    getCustInfo("Lee", 1234, "[e-mail]");
} catch (e) {
    if (e == "InvalidNameException") {
        bad_name_handler(e);
    } else if (e == "InvalidIdException") {
        bad_id_handler(e);
    } else if (e == "InvalidEmailException") {
        bad_email_handler(e);
    } else {
        logError(e);
    }
}