React Native POST Method Issues - json

Question

I have read many questions similar to mine but none solved my issue,
my fetch (Get Method) is working fine but the (POST METHOD) shows Unexpected end of JSON input
fetch('http://monasabat-app.com/Queries/sub_cat.php', {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({
id: 3
}),
}).then((response) => response.json())
.then((responseJson) => {
this.setState({
fsubCategory: responseJson.sub_cat
})
})
.catch((error) => {
console.error(error);
});
}
And this is the response I got by POSTMAN
{
"sub_cat": [
{
"id": "4",
"sub_cat": "sbu1",
"img_path": "url"
},
{
"id": "9",
"sub_cat": "sub2",
"img_path": "url"
}
]
}

Answer 1

Even if you try in postMan using Content-Type: application/json you will notice you don't get any response.
POST /Queries/sub_cat.php HTTP/1.1
Host: monasabat-app.com
Accept: application/json
Content-Type: application/json
Cache-Control: no-cache
Postman-Token: c60774f8-1aaa-4cf8-8aa3-abcab34b05e3
{id:3}
The unexpected end of JSON input it's because it's trying to parse an empty string.
So it's not an issue related to fetch, just try the following to get the proper response:
fetch('http://monasabat-app.com/Queries/sub_cat.php', {
method: 'POST',
headers: {
'Content-Type':'application/x-www-form-urlencoded',
},
body: 'id=3',
})