sirlone

    // in some util.ts or helpers.ts
    export function keysOf<T extends string>(obj: { [k in T]: unknown }): readonly T[] {
       return Object.keys(obj) as unknown[] as T[];
    }

    //---

    const kOperationsFunctions = {
       add(a: number, b: number) { return a + b; },
       subtract(a: number, b: number) { return a - b; },
       multiply(a: number, b: number) { return a * b; },
       divide(a: number, b: number) { return a / b; },
    };
    const kOperations = keysOf(kOperationsFunctions);
    type Operation = (typeof kOperations)[number];

    // put this in some util.ts or enum.ts file
    function makeEnum<T extends readonly string[]>(keys: T) {
        return Object.fromEntries(keys.map((x) => [x, x])) as {
            [K in (typeof keys)[number]]: K
        };
    }

    const SMS_TYPES = makeEnum(['bulk', 'marketing', 'pin', 'signup', 'transaction', 'test'] as const);
    type SMS_TYPE = keyof typeof SMS_TYPES;