Trouble with Fetch in React with CORS
You should convert the fetch response first with .json(). It returns a promise, so you can use it this way:
fetch(url, { crossDomain:true, method: 'POST', headers: {'Content-Type':'application/json'}, body: JSON.stringify({ username: user, password: pass, })}) .then(response => response.json()) .then(responseJson => { console.log(responseJson); const tokenInfo = this.state.token; if (tokenInfo !== undefined) {...See https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch.