wkd-hash

Generate WKD-style hashes for email addresses and usernames. Works in browsers and Node.js.

• ESM-only package
• Node >= 16 (uses Web Crypto or Node's webcrypto)
• Zero deps, ships TypeScript types

Install

npm install wkd-hash

Usage

Node.js (ESM)

import { wkdHash } from "wkd-hash";

const hash = await wkdHash("[email protected]");
console.log(hash); // "aeii9rmagouy1owpp7e5ftpxjof7h41n"

Node.js (CommonJS via dynamic import)

This package is ESM-only. From CommonJS, use a dynamic import:

(async () => {
  const { wkdHash } = await import("wkd-hash");
  const hash = await wkdHash("hi");
  console.log(hash); // "aeii9rmagouy1owpp7e5ftpxjof7h41n"
})();

Browser

Use via a bundler, or import directly from a CDN that supports ESM:

<script type="module">
  import { wkdHash } from "https://cdn.jsdelivr.net/npm/wkd-hash/+esm";
  const hash = await wkdHash("[email protected]");
  console.log(hash);
</script>

API

• async function wkdHash(input: string): Promise<string | null>
  • Returns the WKD z-base-32 encoded SHA-1 hash of the lowercased local-part.
  • If input contains @, only the part before @ is used; otherwise the whole string is used.
  • Returns null if input is not a string.

TypeScript types are included:

export declare function wkdHash(input: string): Promise<string | null>;

Examples

• wkdHash('[email protected]') → aeii9rmagouy1owpp7e5ftpxjof7h41n
• wkdHash('hi') → aeii9rmagouy1owpp7e5ftpxjof7h41n (same as above, only local-part is hashed)

How it works

• Trim and lowercase the input
• Extract the local part (before @) if the input looks like an email
• Compute SHA-1 over the UTF-8 bytes of the local-part
• Encode the resulting 20-byte digest using z-base-32 with alphabet: ybndrfg8ejkmcpqxot1uwisza345h769

Web Crypto is used when available (globalThis.crypto.subtle), falling back to Node's crypto.webcrypto.subtle when running in Node.

Notes

• ESM-only: if you need CommonJS, use dynamic import() as shown above or set up a small wrapper.
• Environment requirements: modern browsers or Node >= 16. For best results and native globalThis.crypto, use Node 20+.