TypeError: Failed to execute 'fetch' on 'Window': Invalid value

Question

I've tried to use fetch to call from backend using react, without libs (such as Axios). So I created this function:

export function api(url, method, body, isHeaderContentType,isRequestHeaderAuthentication,header, succesHandler, errorHandler) {
const prefix = 'link';
console.log("url:",prefix+url);
const contentType = isHeaderContentType ? {
    'Content-Type': 'application/json',
} : {};
const auth = isRequestHeaderAuthentication
    ? {
        Authorization: `Bearer ${AuthUtils.getTokenUser}`,
    }
    : {};
fetch(prefix + url, {
    method,
    headers: {
        ...contentType,
        ...auth,
        ...header,

    },
    protocol:'http:',
    body,
})
    .then(response => {
        response.json().then(json => {
            if (response.ok) {
                console.log("method", json);
                if (succesHandler) {
                    succesHandler(json)
                }
            } else {
                return Promise.reject(json)
            }
        })
    })
    .catch(err => {
        console.log("error",`${url}  ${err}`);
        if (errorHandler) {
            errorHandler(err);
        }
    })

} and call it like this

api(
            `link`,
            "GET",
            null,
            true,
            true,
            null,
            response => {
                this.setState({profile:response.data})
            },
            err => {
                console.log('error', err);
            }
        );

i call my api() inside this function:

getProfileUser = () =>{
    if (!isUserAuthenticated()){
        history.push('/signin')
    }else {
        api(
            `link`,
            "GET",
            null,
            true,
            true,
            null,
            response => {
                this.setState({profile:response.data})
            },
            err => {
                console.log('error', err);
            }
        );
    }
};

this is my full component:

export default class Profile extends Component {
constructor(props) {
    super(props);
    this.state = {
        profile:[]
    }

}
getProfileUser = () =>{
    if (!isUserAuthenticated()){
        someCode
    }else {
        api(
            `link`,
            "GET",
            null,
            true,
            true,
            null,
            response => {
                this.setState({profile:response.data})
            },
            err => {
                console.log('error', err);
            }
        );
    }
};

componentDidMount() {
    this.getProfileUser();
}

render(){
    return(
        <div>
            hello 
        </div>
    )
}

}

but when i tried to run it, i got an error like this

TypeError: Failed to execute 'fetch' on 'Window': Invalid value

Is there anyone who knows what's wrong with my code? The function works when I use the "POST" method, but it doesn't work when I use "GET" method

Answer 1

This also happened to me when I tried to add an Authorization header to my fetch calls. In my case it was caused by a newline character in the header string, i.e. Bearer:\nsomelong-token. Changing the new line to a space solved the problem.