let url = 'https://someurl.com';
let options = {
            method: 'POST',
            mode: 'cors',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json;charset=UTF-8'
            },
            body: JSON.stringify({
                property_one: value_one,
                property_two: value_two
            })
        };
if (response && response.ok) {
    let jsonData = await fetch(url, options).json(); //responseObj.json()
}

react's default dev port is 3000.
I'd like to use another port(80).

Uncaught TypeError: someState.map is not a function