hash-fns

easily create, assess, and assure hashes within a pit-of-success

install

npm install hash-fns

use

for example

import { Hash, toHashSha256, isHashSha256 } from 'hash-fns';

// create a hash
const versionHash: Hash = await toHashSha256('some data');

// verify that a given value is a valid hash
const foundHash: Hash = isHashSha256.assure('__hash__');

// typeguard against random strings being passed as hashes
const expectHash: Hash = 'some string'; // 🛑 typescript will throw an error, since string is not assignable to Hash

// use a hash within functions that expect strings
const expectWords: string = await toHashSha256('some data'); // ✅ passes, as Hash is assignable to strings

🔧 mechs

asHashMd5(message: string): Promise<Hash>

• .what: creates a 128-bit MD5 hash from a UTF-8 string
• .why: fast and compact for non-secure use cases like fingerprinting, deduplication, or cache busting

example:

const cacheKey = await asHashMd5('GET /api/resource?id=123');

---

asHashSha256(message: string): Promise<Hash>

• .what: creates a 256-bit SHA-256 hash from a UTF-8 string
• .why: cryptographically secure hash for versioning, signatures, and data integrity

example:

const versionTag = await asHashSha256(JSON.stringify(configObject));

---

asHashShake256(message: string, options?: { bytes: number }): Promise<Hash>

• .what: creates a variable-length cryptographic hash using SHAKE256 (Keccak sponge function)
• .why: ideal when you need a specific hash length, such as for compact tokens, extended fingerprints, or key material

example:

const customHash = await asHashShake256('some secret', { bytes: 64 }); // 512-bit output