How to create new custom functions as the built in functions...?

[fernandogmar]

Hi again

I am trying to do this kind of function:

game_message = { FLAG($is_ready) ->
    *[inactive]  Insert coin
     [active]   Choose your hero
}

But no idea how to do it... I don't know how to get the flag_value:

    const functions = {
        FLAG(flag_value) {
            return flag_value? 'active' : 'inactive';
        }
    };
    const mc = new MessageContext(config.locale, { functions });

[stasm]

(Please file issues about the JavaScript implementation in https://github.com/projectfluent/fluent.js.)

Fluent Functions, including custom builtins, take positional arguments as well as keyword arguments, which isn't supported by JavaScript out of the box. So instead, we make them accept two arguments: an array of positional args and an object keyword args.

See the example of NUMBER here: https://github.com/projectfluent/fluent.js/blob/dddb5db19bd5fc6a95a251cd7059cf26f187548d/fluent/src/builtins.js#L17

And here's the line which calls Functions: https://github.com/projectfluent/fluent.js/blob/dddb5db19bd5fc6a95a251cd7059cf26f187548d/fluent/src/resolver.js#L417

I think your example should work if you change the FLAG function as follows:

// Destructure the array of positional arguments to flag_value.
FLAG([flag_value]) {
    return flag_value? 'active' : 'inactive';
}

[stasm]

BTW this is a really nice usage of custom builtins!

[fernandogmar]

Thanks!
I was having a look previously to NUMBER builtin... but I didn't get the right answer 😅 And probably because I had to fix another issue first...

So now your suggestion does the trick really well ;)

// Destructure the array of positional arguments to flag_value.
FLAG([flag_value]) {
    return flag_value? 'active' : 'inactive';
}

Thanks again for your fast answer ;) I will post anything related with the implementation on fluent.js next time ;)

[stasm]

I'm happy I was able to help!