@ibgib/helper-gib/src/assumptions.respec.mts

common helper/utils/etc used in ibgib libs. Node v19+ needed for heavily-used isomorphic webcrypto hashing consumed in both node and browsers.

/**
 * @module assumptions.spec.msg
 *
 * This library assumes that we have an environment that allows isomorphic JavaScript
 * via crypto.subtle.
 */

import { respecfully, ifWe, iReckon } from './respec-gib/respec-gib.mjs';
const maam = `[${import.meta.url}]`, sir = maam;

/**
 * wrapper that uses crypto.subtle under the hood (i.e. doesn't hash using
 * external lib).
 *
 * notes:
 *
 * * this is a good spec to include in any consuming library (e.g. core-gib).
 * * i did in fact copy this from ts-gib `hash` fn though (now in helper-gib),
 *   but we're testing simply that the context (node/browser/whatever) has this
 *   since it's integral to all things ibgib.
 */
async function cryptoSubtleHash({
    s,
    algorithm = 'SHA-256',
}: {
    s: string,
    algorithm?: string,
}): Promise<string> {
    let { subtle } = globalThis.crypto;
    if (!s) { throw new Error(`[${cryptoSubtleHash.name}] s is required`) }
    if (!algorithm) { throw new Error(`[${cryptoSubtleHash.name}] algorithm is required`) }
    try {
        const msgUint8 = new TextEncoder().encode(s);
        const buffer = await subtle.digest(algorithm, msgUint8);
        const asArray = Array.from(new Uint8Array(buffer));
        return asArray.map(b => b.toString(16).padStart(2, '0')).join('');
    } catch (e) {
        console.error(e.message ?? e);
        throw e;
    }
}

await respecfully(sir, `non-ts-gib isomorphic crypto hashing`, async () => {

    await ifWe(sir, `should digest simple string consistently using crypto.subtle directly `, async () => {
        let h = await cryptoSubtleHash({ s: '42' });
        iReckon(sir, h).asTo('42').isGonnaBe('73475cb40a568e8da8a045ced110137e159f890ac4da883b6b17dc651b3a8049');
    });
    ifWe(sir, `should digest simple stringified ibgib consistently using crypto.subtle directly `, async () => {
        let ibgib: any = { ib: 'ib', gib: 'gib' };
        let h = await cryptoSubtleHash({ s: JSON.stringify(ibgib) }); // doesn't use ts-gib but consistent stringifying json is important
        iReckon(sir, h).asTo('ib^gib').isGonnaBe('cbad0694a257358c044611ea1fa88ace71a01a9b8409d2354d0387d8043f7671');
    });
});