NodeJS mongoose bug in if statement - node.js

Question

The code should work like that: If target username and logged in user username is in the same fight then the fight should not be created and user should be redirected to /arena. But the problem is that even though when I finish the fight then fast hit F5 the new fight with the same user and same target creates again. What could cause this problem ?
app.get('/arena/fight/user/:username', async (req, res) => {
User.findById(req.session.userId).then((user) => {
if(req.params.username === user.username) {
return res.redirect('/arena');
}
});
const target = await User.findOne({username: req.params.username});
const user = await User.findById(req.session.userId);
const fight = await TempFight.findOne({user: user.username});
if(fight && target.username === fight.target) {
return res.redirect('/arena');
} else {
const battleId = uuid4();
const newtempFight = TempFight({
target: target.username,
user: user.username,
code: battleId
});
await newtempFight.save();
}
if(req.session.userId) {
res.render(__dirname + '/views/arena/battle', {messages, user, enemy, userItems, enemyItems, liveitems, fights, lostFights});
} else {
return res.redirect('/');
}
});

Answer 1

Try this
app.get('/arena/fight/user/:username', async (req, res) => {
const user = await User.findById(req.session.userId);
if(req.params.username === user.username) {
return res.redirect('/arena');
}
const target = await User.findOne({username: req.params.username});
const fight = await TempFight.findOne({user: user.username});
if(fight && target.username === fight.target) {
return res.redirect('/arena');
} else {
const battleId = uuid4();
const newtempFight = TempFight({
target: target.username,
user: user.username,
code: battleId
});
await newtempFight.save();
}
if(req.session.userId) {
res.render(__dirname + '/views/arena/battle', {messages, user,
enemy, userItems, enemyItems, liveitems, fights, lostFights});
} else {
return res.redirect('/');
}
});