@hexdspace/core

Primitives shared across projects. No runtime dependencies.

Result

import { type AsyncResult, type Result, mapOk, nok, ok, unwrapOr } from '@hexdspace/core';

function parsePort(raw: string): Result<string, number> {
    const port = Number(raw);
    return Number.isInteger(port) ? ok(port) : nok(`Bad port: ${raw}`);
}

const result = parsePort('8080');
if (result.ok) {
    result.value;
} else {
    result.error;
}

unwrapOr(mapOk(result, (port) => port + 1), 3000);

The error type comes first: Result<E, T> and AsyncResult<E, T>.

| Function | Purpose | | --- | --- | | ok(value), nok(error) | construct a result | | isOk(result), isNok(result) | type guards | | mapOk(result, transform) | transform the value | | mapError(result, transform) | transform the error | | unwrap(result) | return the value or throw the error | | unwrapOr(result, fallback) | return the value or the fallback |

Testing

@hexdspace/core/testing has vitest assertions that narrow the type:

import { expectResultError, expectResultOk } from '@hexdspace/core/testing';

expectResultOk(result);
result.value;