Generate unique ID like Firebase Firestore

I want to create a document in firestore with an unique id and a name after the unique id. For this, I want to create the same kind of the firebase firestore unique ids.

• How can I create an unique ID with the kind of a auto generated firestore id?
• Is there a function in the Firebase Admin SDK?

UPDATE:

As Frank van Puffelen mentied in the comments, the AutoId is the right choice for me!

Here is the function I use on server-side with node.js:

function generateUniqueFirestoreId(){
  // Alphanumeric characters
  const chars =
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
  let autoId = '';
  for (let i = 0; i < 20; i++) {
    autoId += chars.charAt(Math.floor(Math.random() * chars.length));
  }

  return autoId;
}