keycloak_theme/test/lib/tools/AndByDiscriminatingKey.ts

import { AndByDiscriminatingKey } from "keycloakify/tools/AndByDiscriminatingKey";
import { assert } from "tsafe/assert";
import type { Equals } from "tsafe";

{
    type Base =
        | { pageId: "a"; onlyA: string }
        | { pageId: "b"; onlyB: string }
        | { pageId: "only base"; onlyBase: string };

    type Extension =
        | { pageId: "a"; onlyExtA: string }
        | { pageId: "b"; onlyExtB: string }
        | { pageId: "only ext"; onlyExt: string };

    type Got = AndByDiscriminatingKey<"pageId", Extension, Base>;

    type Expected =
        | { pageId: "a"; onlyA: string; onlyExtA: string }
        | { pageId: "b"; onlyB: string; onlyExtB: string }
        | { pageId: "only base"; onlyBase: string }
        | { pageId: "only ext"; onlyExt: string };

    assert<Equals<Got, Expected>>();

    const x: Got = null as any;

    if (x.pageId === "a") {
        x.onlyA;
        x.onlyExtA;

        //@ts-expect-error
        x.onlyB;

        //@ts-expect-error
        x.onlyBase;

        //@ts-expect-error
        x.onlyExt;
    }

    if (x.pageId === "b") {
        x.onlyB;
        x.onlyExtB;

        //@ts-expect-error
        x.onlyA;

        //@ts-expect-error
        x.onlyBase;

        //@ts-expect-error
        x.onlyExt;
    }

    if (x.pageId === "only base") {
        x.onlyBase;

        //@ts-expect-error
        x.onlyA;

        //@ts-expect-error
        x.onlyB;

        //@ts-expect-error
        x.onlyExt;
    }

    if (x.pageId === "only ext") {
        x.onlyExt;

        //@ts-expect-error
        x.onlyA;

        //@ts-expect-error
        x.onlyB;

        //@ts-expect-error
        x.onlyBase;
    }
}

{
    type Base =
        | { pageId: "a"; onlyA: string }
        | { pageId: "b"; onlyB: string }
        | { pageId: "only base"; onlyBase: string };

    type Extension = { pageId: "only ext"; onlyExt: string };

    type Got = AndByDiscriminatingKey<"pageId", Extension, Base>;

    type Expected =
        | { pageId: "a"; onlyA: string }
        | { pageId: "b"; onlyB: string }
        | { pageId: "only base"; onlyBase: string }
        | { pageId: "only ext"; onlyExt: string };

    assert<Equals<Got, Expected>>();
}