Detect error code collisions

[jhnns]

Within the same application, there should not be more than one error class associated with a given error code. Erroz should detect these collisions and throw an error.

var FileNotFound = erroz({
    code: "not-found"
});
// Should throw an Duplicate error code error
var UserNotFound = erroz({
    code: "not-found"
});

[jhnns]

I'm not sure if that's useful for all use cases, but it is surely useful for many.

[meaku]

Nice idea! But it assumes that you have some kind of registry for your errors and it might be inconvenient to bind it to the erroz "instance". How about making it configurable?

[jhnns]

Yes... but a boolean switch on the erroz object like erroz.uniqueErrorCodes = true feels kind of wrong. What about creating "domains":

// creating domains for error codes
erroz.domain("api");
erroz.domain("db");

// later
erroz.domain.api({
    code: "not-found"
}); // ok
erroz.domain.db({
    code: "not-found"
}); // ok
erroz.domain.api({
    code: "not-found"
}); // throws Duplicate Error Code

With ES2015 Proxies, we could even omit the first step of creating domains. This would be done implicitly by intercepting all property retrievals on erroz.domain.

[meaku]

Sounds good! I'd still add erroz.uniqueErrorCodes = true with default = true to make this behavior configurable.

Scheduled for the next release 👍

[jhnns]

But if we have domains, we don't need an erroz.uniqueErrorCodes option imho

[meaku]

But domains are optional right? If we only add the feature for domains its fine to kick the option. Otherwise i would add the option for "global" errors.

[jhnns]

Yes, domains are optional. But if you don't use domains, erroz won't check for duplicate error codes (just the current behavior)

[meaku]

Easy ™️