What does flat code mean?

Question

Programming

Everywhere they write flat asynchronous code or written in a flat way. What does flat code mean?

Answer 1

Code that is written and read as if it were not asynchronous at all (all calls are one after the other).
js example

const parseAdminsData = async ()=>{
  const token = await getToken();
  const users = await getUsers(token);
  const admins = users.filter(({isAdmin})=>isAdmin);
  return admins;
}

here are two asynchronous requests, but in the code they just look like function calls. (no callbacks)

Answer 2

nested code (nested):

for a in range(10):
    for b in range(20):
        for c in range(30):
            for d in range(40):
                if d == 1:
                    if c == 1:
                        if b == 1:
                             if a == 1:
                                  print('nested code')

flat code (flat):

for a in range(10):
    print('flat code')

it is clear that the nested code is read very badly - therefore, you should try to write flat code, this will save you time in a few months and the other person who will read the code.
in addition, nested code is slower than flat code and is more likely to be reduced to flat code.