Error: Cannot read property 'token' of undefined - reactjs

Question

I have a function api inside the method onSubmit, which make request to the server:
onSubmit: async (formValues) => {
setSubmitting(true);
try {
const res = await api('api/auth/register', {
method:'POST',
body: JSON.stringify(formValues)
});
if(Array.isArray(res)){
setErrorMessage(res[0].message);
} else {
const token = res.token.token;
localStorage.setItem('myToken', token);
history.push("/home");
}
} catch(e) {
console.error(e);
} finally {
setSubmitting(false);
}
},
});
Function api is in a separate file and looks like this:
export const api = async (url, args) => {
const response = await fetch(`${apiUrl}${url}`, {
...args,
headers: {
"Content-type": "application/json; charset=UTF-8 ",
"Accept": 'application/json',
...args.headers,
},
});
return response.json();
}
This function was created simply for convenience. But now I dont need this function. I need that code from api was inside method onSubmit. That is, that the function api not exist at all.
And I did it:
onSubmit: async (formValues) => {
setSubmitting(true);
try {
const resf = await fetch(`${apiUrl}api/auth/register`, {
method:'POST',
body: JSON.stringify(formValues),
headers: {
"Content-type": "application/json; charset=UTF-8 ",
"Accept": 'application/json',
}
});
const res = resf.json();
if (Array.isArray(res)){
setErrorMessage(res[0].message);
} else {
const token = res.token.token;
localStorage.setItem('myToken', token);
history.push("/home");
}
} catch(e) {
console.error(e);
} finally {
setSubmitting(false);
}
},
});
But I have error:
TypeError: Cannot read property 'token' of undefined
Why is this error occurring?

Answer 1

Try with await for resf.json() because calling .json() gets you another promise for the body of the http response that is yet to be loaded.
const res = await resf.json();