roblox-ts•2mo ago

How to make discriminated union exhaustive while using t

const GAME_MODES = ["STANDARD", "TOURNAMENT", "CRAZY"] as const;
export type GameMode = (typeof GAME_MODES)[number];

export const gameModeToNameMap: Record<GameMode, string> = {
    STANDARD: "Standard",
    TOURNAMENT: "Tournament",
    CRAZY: "Crazy",
};

const isBaseGameOptions = t.interface({
    gridSize: t.interface({
        rows: dimensionCheck,
        columns: dimensionCheck,
    }),
    time: t.union(...timeControlOptions),
});

const isStandardGameOptions = t.intersection(
    isBaseGameOptions,
    t.interface({
        gameMode: t.literal("STANDARD"),
    }),
);

const isTournamentGameOptions = t.intersection(
    isBaseGameOptions,
    t.interface({
        gameMode: t.literal("TOURNAMENT"),
        winThreshold: t.numberConstrained(3, 10),
    }),
);

// export const isGameOptions = t.interface({
//     gameMode: t.valueOf(GAME_MODES),
//     gridSize: t.interface({
//         rows: dimensionCheck,
//         columns: dimensionCheck,
//     }),
//     time: t.union(...timeControlOptions),
// });

export const isGameOptions = t.union(isStandardGameOptions, isTournamentGameOptions);
export type GameOptions = t.static<typeof isGameOptions>;

const GAME_MODES = ["STANDARD", "TOURNAMENT", "CRAZY"] as const;
export type GameMode = (typeof GAME_MODES)[number];

export const gameModeToNameMap: Record<GameMode, string> = {
    STANDARD: "Standard",
    TOURNAMENT: "Tournament",
    CRAZY: "Crazy",
};

const isBaseGameOptions = t.interface({
    gridSize: t.interface({
        rows: dimensionCheck,
        columns: dimensionCheck,
    }),
    time: t.union(...timeControlOptions),
});

const isStandardGameOptions = t.intersection(
    isBaseGameOptions,
    t.interface({
        gameMode: t.literal("STANDARD"),
    }),
);

const isTournamentGameOptions = t.intersection(
    isBaseGameOptions,
    t.interface({
        gameMode: t.literal("TOURNAMENT"),
        winThreshold: t.numberConstrained(3, 10),
    }),
);

// export const isGameOptions = t.interface({
//     gameMode: t.valueOf(GAME_MODES),
//     gridSize: t.interface({
//         rows: dimensionCheck,
//         columns: dimensionCheck,
//     }),
//     time: t.union(...timeControlOptions),
// });

export const isGameOptions = t.union(isStandardGameOptions, isTournamentGameOptions);
export type GameOptions = t.static<typeof isGameOptions>;

I wanted to start adding custom rules depending on the game mode selected (right now only standard and tournament mode are available) but for demonstration purposes I added a "crazy" mode to show my problem. How can I enforce that my isGameOptions contains all game modes in the GAME_MODES array? This code would work without errors

Solution:

Apparently flamework/core is enough

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10 Replies

Tester•2mo ago

do you use flamework?

PhantomOP•2mo ago

Tester•2mo ago

can you make an empty project with flamework template, generate the t from type and take it from compiled code? ^ i think it's gonna be way easier cause you can define the structure in the type and the flamework will do the figuring out for t structure

interface IData{
   Gems: number;
   Name: string;
   ClassesList: keyof Instances;
}
const guard = Flamework.createGuard<IData>(); //and can you check the transpiled code for that part?

interface IData{
   Gems: number;
   Name: string;
   ClassesList: keyof Instances;
}
const guard = Flamework.createGuard<IData>(); //and can you check the transpiled code for that part?

PhantomOP•2mo ago

i cant exactly migrate to flamework but i think i can make a guard

type ContainsGameModes<T extends { gameMode: GameMode }> = GameMode extends T["gameMode"] ? T : never;

type ContainsGameModes<T extends { gameMode: GameMode }> = GameMode extends T["gameMode"] ? T : never;

this seems to work. would you have any better ideas? preferably it would throw a typeError instead of just defaulting to never but i am unfortunately not a type wizard

Tester•2mo ago

can you ask ai to make a type? i usually do that if the type is complex 🙄

Unknown User•2mo ago

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PhantomOP•2mo ago

is there a smaller package i could use for that? is it @flamework/networking

Tester•2mo ago

Wdym? So you want it for networking? I think flamework is 3 packages @flamework/core (has to be all the time) @flamework/networking @flamework/components Or it might be 4 cause flamework has a transformer I think, or it's embedded in core

PhantomOP•2mo ago

i want the type guards

Solution

Tester•2mo ago

Apparently flamework/core is enough

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How to make discriminated union exhaustive while using t

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