pseudo-uuid.js

// Generate a deterministic pseudo UUID (v4), such that the same input always gives the same output.
// Potentially useful for test mocks or such where a specific datum is associated to a specific UUIDs,
// but doesn't need guarantees against clashing.

// With ES6 modules, you can remove the "require" part, and instead import like this:
// import { createHash } from "crypto";

const pseudoUuid = (input) => require("crypto")
  .createHash("sha256")
  .update(input)
  .digest("hex")
  .replace(/(.{8})(.{4})(.{4})(.{4})(.{12}).*/, "$1-$2-$3-$4-$5");

console.log(pseudoUuid("hello")); // '2cf24dba-5fb0-a30e-26e8-3b2ac5b9e29e'
console.log(pseudoUuid("hello")); // '2cf24dba-5fb0-a30e-26e8-3b2ac5b9e29e'
console.log(pseudoUuid("bork"));  // 'b662ae3a-bc79-8cf6-27f3-1727cf1ea4e0'