invalid json with valid json (verified with online tool) - node.js

Question

Unfortunately this was due to another unrelated part of my code. This is an invalid question. Sorry.
I am getting an invalid json response body error on my client using fetch() to a RESTFUL api.
This is my server POST code that is called by the client using this code:
.then(conn => {
conn.query("SELECT MAX(`messagesMinute`) FROM `statistics` LIMIT 1;")
.then(rows => { // rows: [ {val: 1}, meta: ... ]
var data = {
'messagesMinuteMAX': Object.values(rows[0])[0] // ugly ass code but i dont know a better way after searching for a while
}
res.json(JSON.stringify(data));
res.end();
})
This is my client code that uses fetch
// Request the highscore of messages per minute
fetch("http://localhost:3001/postRequestMinute", { method: 'GET', headers: {} })
.then((res) => {
return res.json();
})
.then(async (json) => {
console.log(json); // <<<<---- this is the log that retrieves the following
}).catch((err) => {
console.log(err);
});
The console.log that sends out the json response returns this:
{ "messagesMinuteMAX": 1341 }
This is verified as valid with multiple online json validaters.
My biggest problem with all of this is that everything works as intended, but it spits out this error anyways which is very annoying.

Answer 1

Maybe its your
res.json(JSON.stringify(data));
This what happend when I did in nodejs console
> a = [{ type: 'text', text: 'Hello, world1' }]
[ { type: 'text', text: 'Hello, world1' } ]
> JSON.stringify(JSON.stringify(a))
'"[{\\"type\\":\\"text\\",\\"text\\":\\"Hello, world1\\"}]"'
when you stringify 2 times you got 2 quote outside your object

Answer 2

After fetch API, try to use JSON.parse(object_string)
Hope it works for you
Tip: use typeof(variable) to verify variable type
let result
fetch("http://localhost:3001/postRequestMinute", { method: 'GET', headers: {} })
.then((res) => {
console.log(JSON.parse(res))
result = JSON.parse(res)
}).catch((err) => {
console.log(err);
});

Answer 3

Unfortunately this was due to another unrelated part of my code. This is an invalid question. Sorry.