Firebase: how to generate a unique numeric ID for key?

Question

I need numeric IDs for human readability. How do I get it in Firebase?

I want numeric ID for keys, e.g. \"000000001\", \"000000002\",\"00000003\",\"00000004\".

Answer 1

Adding to the @htafoya answer. The code snippet will be

const getTimeEpoch = () => {
    return new Date().getTime().toString();                             
}