How to get different sequence in node js

I have some question, I have some sequence number, examp 123456

when some user get that sequence number (from file, redis or db) and increment thats sequence.

let says
user1  get 123456
user2  get 123456
user3  get 123456
user4  get 123456
user5  get 123456
user6  get 123456
user7  get 123456

and my question is, how nodeJS can handle this problem in simultan request? because i hope i can get this

let says
user1  get 123456
user2  get 123457
user3  get 123458
user4  get 123459
user5  get 123460
user6  get 123461
user7  get 123462

because when i request one by one, thats no problem, but when i use looping 1-7, it seem the request was process simultaneously, that why every user get same id.

 let firstData = result[0];  < ---- get from promise (db, redis or something

 nextData = firstData + 1;

 console.log(userid+" "+nextData); 

via Susan Lie