npm i react-uuid
import React from 'react' import uuid from 'react-uuid' const array = ['one', 'two', 'three'] export const LineItem = item => <li key={uuid()}>{item}</li> export const List = () => array.map(item => <LineItem item={item} />)
function uuid() { return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) { var r = Math.random() * 16 | 0, v = c == 'x' ? r : (r & 0x3 | 0x8); return v.toString(16); }); } var userID=uuid();//something like: "ec0c22fa-f909-48da-92cb-db17ecdb91c5"