Convert UUIDv4 to UUIDv7 in JavaScript (or generate one) [RFC 9562]

uuid4to7.js

const uuid4to7 = (uuid, now = Date.now()) => {
  const ts = now.toString(16).padStart(12, `0`)

  return `${ts.slice(0, 8)}-${ts.slice(8)}-7${uuid.slice(15)}`
}

// generate new UUIDv7
uuid4to7(crypto.randomUUID())

// Conforms to example in the spec RFC9562 A.6
// https://www.rfc-editor.org/rfc/rfc9562.html#name-example-of-a-uuidv7-value
uuid4to7(
  `6ed0cbe6-d1fb-4cc3-98c4-dc0c0c07398f`,
  Date.parse(`2022-02-22T14:22:22-05:00`)
)
// -> `017f22e2-79b0-7cc3-98c4-dc0c0c07398f`