I have a mapping
"balances": {
"1": "1000",
"2": "2000",
"3": "3000",
}
How do return 0 if the account number cant be found?
my code so far is
app.get('/GetBalanceByAddress/:id', function (req, res) {
res.end(JSON.stringify(balances.balances[req.params.id], null, 4));
});
for example, right now /GetBalance/1 returns 1000
/GetBalance/2 returns 2000
/GetBalance/3 returns 3000
and /GetBalance/4 returns nothing.
How do i get /GetBalance/(AnyNonExistentAddress) to return 0?
Right, please use try catch or if statement.
app.get('/GetBalanceByAddress/:id', function (req, res) {
try{
res.end(JSON.stringify(balances.balances[req.params.id]));
}
catch{
res.end("0");
}
});
or
app.get('/GetBalanceByAddress/:id', function (req, res) {
if (balances.balances[req.params.id]) {
res.end(JSON.stringify(balances.balances[req.params.id]));
}
else {
res.end("0");
}
});
If you're using an ES2020 compatible browser, you can use the nullish coalescing operator:
const balances = { "balances": {
"1": "1000",
"2": "2000",
"3": "3000",
}
};
let id = 1;
console.log(balances.balances[id] ?? 0);
id = 4;
console.log(balances.balances[id] ?? 0);you could wrap in a try/catch block
app.get('/GetBalanceByAddress/:id', function (req, res) {
try{
res.end(JSON.stringify(balances.balances[req.params.id], null, 4));
});
}
catch{
return 0;
}