functionalscript/types/nominal/test.f.js

FunctionalScript is a purely functional subset of JavaScript

import { asBase, asNominal } from "./module.f.js";
export default {
    pre: () => {
        const strA = asNominal(7560413859n); // "¢£"
        const strB = asNominal(7560413860n); // "¢¤"
        if (strA === strB) {
            throw [strA, strB];
        }
        // // TypeScript compilation error.
        // const x1 = strA > strB
        //
        {
            const a = { value: 1 };
            const b = { value: 2 };
            // No Compile-time error
            if (a < b) { }
        }
        {
            const x = { _brand: 'NoCompare' };
            // No Error
            if (x < x) { }
        }
        {
            const a = {};
            const b = {};
            // No Error
            a < b;
        }
        {
            const a = undefined;
            const b = undefined;
            // a < b; // TS2469: Operator '<' cannot be applied to type 'symbol'.
        }
    },
    nominal: () => {
        const userIdA = asNominal(123);
        const userIdB = asNominal(456);
        if (userIdA === userIdB) {
            throw [userIdA, userIdB];
        }
        const to = asBase;
        const to2 = asBase;
        const userId2A = asNominal(123);
        const userId2B = asNominal(456);
        if (userId2A === userId2B) {
            throw [userId2A, userId2B];
        }
        // if (userIdA === userId2A) { throw [userIdA, userId2A] } // compilation error
        const n1 = to(userIdA);
        const n2 = to2(userId2A);
        // const x = to(userId2A) // compilation error
    }
};