Best way to programmatically manage exceptions handled by a NodeJS application

[justin hyland]

I'm working on a NodeJS application right now, and I'm somewhat stuck on the "best" way to manage exceptions that can be returned (or thrown) by the application.

The two things I would like to accomplish are:

Localization - Instead of the exceptions being hardcoded in English, would be nice if the messages and details were stored in files, so they can easily be switched out to change the language (since thats how the l10n in the rest of the application will work as well)

As opposed to having the exception messages hardcoded and spread out everywhere, I'm hoping to have it setup so all of the exceptions are stored in one place, and when an exception needs to be thrown, I can simply reference the specific exception by its "key" or "code", and provide any details that can be used to fill in some blanks in the exception messages.

I have a basic version of this setup in the application right now, and I copied the relevant parts over to a temporary Github repo, just as an example of what I mean.

Basically, you can see I have the details that are returned by the exceptions stored in a series of files (like this one), and when an exception needs to be thrown, I can reference the key of whatever exception needs to be thrown (EG: account.login.badPassword would be used when someone tries to authenticate with an incorrect password), and provide any data that the exception will need to display.

Heres an example of how to throw one of the exceptions, and how data is provided for string substitution in the exception details (this is located in the app.js):

const AppError = require( "./exceptions" ).init


try {
    throw new AppError({
        code: 'account.login.badUsername',
        data: 'j.doe'
    })
}
catch( e ){
    console.log('%s - %s',e.name, e.message)
    console.log(e)
}

So the above example throws an exception using the code account.login.badUsername, and it provides the string j.doe in the data property. So looking at the exceptions stored in the account.js file again, you can see the detail property is The username provided (%s) was not found., so when the exception gets thrown, the completed exception will look like: The username provided (j.doe) was not found.

The logic for retrieving the exception data via the exception code provided, (as well as the string substitution in the exception details,) can be found in the file.

Down to the question....

Is this the "best" way to accomplish what I'm trying to accomplish? or is there another way to go about doing this that may be easier and cleaner? So far, it seems to be working ok, I'm just afraid that ill finish the first version of this app, and someone will be like "Oh why are you managing exceptions like that? why didn't you just __________??".

Any input is appreciated!

Thanks

P.S. I apologize if this ends up being a duplicate post. I thought I posted the question here, but that was a few days ago, and it hasnt shown up.