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Using Fetch API to create a Login form

So, I am making a login form and I have already implemented the fetch API
const form = {
email: document.querySelector("#signin-email"),
password: document.querySelector("#signin-password"),
submit: document.querySelector("#signin-btn-submit"),
messages:document.getElementById("form-messages")
};
let button = form.submit.addEventListener("click", (e)=> {
e.preventDefault();
const login = 'https://ffcc-app.herokuapp.com/user/login';
fetch(login, {
method: "POST",
headers: {
Accept: "application/json, text/plain, */*",
"Content-Type": "application/json",
},
body: JSON.stringify({
email: form.email.value,
password: form.password.value,
}),
})
.then((response) => response.json())
.then((data) => console.log(data))
.catch((err) => {
console.log(err);
});
});
I am also getting the desired output:
The problem is I have to redirect to the main page when 'login successful' else I have to display a message saying 'user does not exist'. how should I do that? What else should I add to my code?

const form = {
email: document.querySelector("#signin-email"),
password: document.querySelector("#signin-password"),
submit: document.querySelector("#signin-btn-submit"),
messages: document.getElementById("form-messages"),
};
let button = form.submit.addEventListener("click", (e) => {
e.preventDefault();
const login = "https://ffcc-app.herokuapp.com/user/login";
fetch(login, {
method: "POST",
headers: {
Accept: "application/json, text/plain, */*",
"Content-Type": "application/json",
},
body: JSON.stringify({
email: form.email.value,
password: form.password.value,
}),
})
.then((response) => response.json())
.then((data) => {
console.log(data);
// code here //
if (data.error) {
alert("Error Password or Username"); /*displays error message*/
} else {
window.open(
"target.html"
); /*opens the target page while Id & password matches*/
}
})
.catch((err) => {
console.log(err);
});
});
login sucess and error handled by data.error as mentioned in your screenshot
👉 https://i.stack.imgur.com/WJBh2.png

function signIn(email, password) {
var userObj = {email: email, password: password};
var jsonBody = JSON.stringify(userObj);
fetch(server + "/auth/authorization", {
// mode: "no-cors",
method: 'POST',
headers: {
"Accept-language": "RU",
"Content-Type": "application/json"
},
body: jsonBody
})
.then(response => response.json())
.then(data => {
if (data.error) {
alert("Error Password or Username");
} else {
return data;
}
})
.catch((err) => {
console.log(err);
});
}

AsyncStorage works only when app is reloaded

i set my values in Async storage while logging
fetch('http://xxxxx/xxxx/getUserDetails.php', {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({
user_id: this.state.userEmail,
})
})
.then((response) => response.json())
.then((responseJson) => {
const name = responseJson[0]['name'];
const profilePicture = responseJson[0]['profile_picture'];
const userId = responseJson[0]['id'];
const loginMode = responseJson[0]['login_mode'];
AsyncStorage.setItem('active', 'true');
AsyncStorage.setItem('userEmail', this.state.userEmail);
AsyncStorage.setItem('name', name);
AsyncStorage.setItem('profilePicture', profilePicture);
AsyncStorage.setItem('userID', userId);
AsyncStorage.setItem('loginMode', loginMode)
setTimeout(async () => {
this.setState({ isLoading: false })
this.props.navigation.navigate('userScreen');
}, 500)
})
.catch((error) => {
console.log(error);
})
}
and delete those while logging out.
fetch('https://xxxxxx/xxxx/userLogout.php', {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({
email: userEmail
})
}).then((response) => response.json())
.then(async (responseJson) => {
try {
const keys = await AsyncStorage.getAllKeys();
await AsyncStorage.multiRemove(keys);
this.props.navigation.toggleDrawer();
this.setState({ isLoading: false })
this.props.navigation.navigate('loginScreen');
} catch (error) {
console.log("Error clearing app data");
}
}).catch((error) => {
console.log(error);
})
but again if i login with new user the old user details is shown in login page. if i reload my app the new values stored in async storage is shown why this is happen and this is not happening?
I am using the AsyncStorage here.
async componentDidMount() {
const userEmail = await AsyncStorage.getItem('userEmail');
const name = await AsyncStorage.getItem('name');
const profilePicture = await AsyncStorage.getItem('profilePicture');
const userID = await AsyncStorage.getItem('userID');
this.getWish();
this.getAddFunction();
this.setState({ userEmail })
this.getResumeVideo(userEmail);
this.getDemoVideo();
this.getClass();
this.setState({
userEmail,
name,
profilePicture,
userID
})
this.getNotificationCount(userID);
Orientation.lockToPortrait();
this._unsubscribe = this.props.navigation.addListener('focus', () => {
this.getAddFunction();
this.getDemoVideo();
this.getResumeVideo(this.state.userEmail);
this.getClass();
this.getNotificationCount(userID);
});
}

The only place you are calling setState and tells react it should assign new value to state (and render...) it at componentDidMount, therefore React don't know it should render again.
When assigning new value to AsyncStorage you might also call setState
fetch('http://xxxxx/xxxx/getUserDetails.php', {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({
user_id: this.state.userEmail,
})
})
.then((response) => response.json())
.then((responseJson) => {
const name = responseJson[0]['name'];
const profilePicture = responseJson[0]['profile_picture'];
const userId = responseJson[0]['id'];
const loginMode = responseJson[0]['login_mode'];
AsyncStorage.setItem('active', 'true');
AsyncStorage.setItem('userEmail', this.state.userEmail);
AsyncStorage.setItem('name', name);
AsyncStorage.setItem('profilePicture', profilePicture);
AsyncStorage.setItem('userID', userId);
AsyncStorage.setItem('loginMode', loginMode)
setTimeout(async () => {
this.setState({ isLoading: false })
this.props.navigation.navigate('userScreen');
}, 500)
// here
this.setState({
name,
profilePicture,
userID
})
})
.catch((error) => {
console.log(error);
})
}

Fetch api response being undefined

This question has been asked but none of the answers helped.
In react native I'm making an api call with this:
getAuthToken = () => {
SecureStore.getItemAsync('authToken')
.then((authToken) => {
console.log(authToken);
fetch('https://example.com?token=' + authToken + '&order_id=5480', {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
}
}
)
})
.then(res => res.json())
.then(result => {
console.log(result)
})
.catch(error => {
console.error(error);
})
}
In post man I can confirm this works:
However console.log(result) keeps returning as undefined.
Any ideas what I'm doing wrong?

Your syntax is a bit off and your then block is not part of your fetch request.
Update to the following and it should work
getAuthToken = () => {
SecureStore.getItemAsync("authToken").then(authToken => {
console.log(authToken);
fetch("https://example.com?token=" + authToken + "&order_id=5480", {
method: "POST",
headers: {
Accept: "application/json",
"Content-Type": "application/json"
}
})
.then(res => res.json())
.then(result => {
console.log(result);
})
.catch(error => {
console.error(error);
});
});
};

React-Redux syntax error "," expected

New to this.
...and this is probably very simple. I have looked at the code for the const "selectData" and I cannot find where a comma is suppose to go. Here is the entire file:
export const requestLoginToken = (username, password) =>
(dispatch, getState) => {
dispatch({ type: REQUEST_LOGIN_TOKEN, payload: username })
const payload = {
userName: username,
password: password,
}
const task = fetch('/api/jwt', {
method: 'POST',
body: JSON.stringify(payload),
headers: {
'Content-Type': 'application/json;charset=UTF-8'
},
})
.then(handleErrors)
.then(response => response.json())
.then(data => {
dispatch({ type: RECEIVE_LOGIN_TOKEN, payload: data })
saveJwt(data)
selectData()
})
.catch(error => {
clearJwt()
dispatch({ type: ERROR_LOGIN_TOKEN, payload: error.message })
})
addTask(task)
return task
}
const selectData = () => {
dispatch({ type: REQUEST_SELECT_DATA })
const token = jwt.access_token
const headers = new Headers({
'Authorization': `Bearer ${token}`
})
const selectData = fetch('/api/SelectData/SelectData', {
method: 'GET',
headers,
})
.then(handleErrors)
.then(response => response.json())
.then(data => {
dispatch({ type: RECEIVE_SELECT_DATA, payload: data })
.catch(error => {
clearJwt()
dispatch({ type: ERROR_SELECT_DATA, payload: error.message })
})
}
}
The error is on the very last curly bracket and it says:
Unexpected token, expected , (72:0)
line 72 is the last curly bracket.
If I remove the const expression that is "selectData" its OK - no errors. The error only appears when I add in that block of code... i.e its in the following:
const selectData = () => {
dispatch({ type: REQUEST_SELECT_DATA })
const token = jwt.access_token
const headers = new Headers({
'Authorization': `Bearer ${token}`
})
const selectData = fetch('/api/SelectData/SelectData', {
method: 'GET',
headers,
})
.then(handleErrors)
.then(response => response.json())
.then(data => {
dispatch({ type: RECEIVE_SELECT_DATA, payload: data })
.catch(error => {
clearJwt()
dispatch({ type: ERROR_SELECT_DATA, payload: error.message })
})
}
}
Why is this block of code causeing an error?

You forgot a ) on the last then:
.then(data => {
dispatch({ type: RECEIVE_SELECT_DATA, payload: data })
.catch(error => {
clearJwt()
dispatch({ type: ERROR_SELECT_DATA, payload: error.message })
})
}) // <--- here
And you should always use ;. I recommend you to use a linter to check your code, like ESLint

Javascript: Fetch DELETE and PUT requests

I have gotten outside of GET and POST methods with Fetch. But I couldn't find any good DELETE and PUT example.
So, I ask you for it. Could you give a good example of DELETE and PUT methods with fetch. And explain it a little bit.

Here is a fetch POST example. You can do the same for DELETE.
function createNewProfile(profile) {
const formData = new FormData();
formData.append('first_name', profile.firstName);
formData.append('last_name', profile.lastName);
formData.append('email', profile.email);
return fetch('http://example.com/api/v1/registration', {
method: 'POST',
body: formData
}).then(response => response.json())
}
createNewProfile(profile)
.then((json) => {
// handle success
})
.catch(error => error);

Ok, here is a fetch DELETE example too:
fetch('https://example.com/delete-item/' + id, {
method: 'DELETE',
})
.then(res => res.text()) // or res.json()
.then(res => console.log(res))

For put method we have:
const putMethod = {
method: 'PUT', // Method itself
headers: {
'Content-type': 'application/json; charset=UTF-8' // Indicates the content
},
body: JSON.stringify(someData) // We send data in JSON format
}
// make the HTTP put request using fetch api
fetch(url, putMethod)
.then(response => response.json())
.then(data => console.log(data)) // Manipulate the data retrieved back, if we want to do something with it
.catch(err => console.log(err)) // Do something with the error
Example for someData, we can have some input fields or whatever you need:
const someData = {
title: document.querySelector(TitleInput).value,
body: document.querySelector(BodyInput).value
}
And in our data base will have this in json format:
{
"posts": [
"id": 1,
"title": "Some Title", // what we typed in the title input field
"body": "Some Body", // what we typed in the body input field
]
}
For delete method we have:
const deleteMethod = {
method: 'DELETE', // Method itself
headers: {
'Content-type': 'application/json; charset=UTF-8' // Indicates the content
},
// No need to have body, because we don't send nothing to the server.
}
// Make the HTTP Delete call using fetch api
fetch(url, deleteMethod)
.then(response => response.json())
.then(data => console.log(data)) // Manipulate the data retrieved back, if we want to do something with it
.catch(err => console.log(err)) // Do something with the error
In the url we need to type the id of the of deletion: https://www.someapi/id

Just Simple Answer.
FETCH DELETE
function deleteData(item, url) {
return fetch(url + '/' + item, {
method: 'delete'
})
.then(response => response.json());
}

Here is good example of the CRUD operation using fetch API:
“A practical ES6 guide on how to perform HTTP requests using the Fetch API” by Dler Ari https://link.medium.com/4ZvwCordCW
Here is the sample code I tried for PATCH or PUT
function update(id, data){
fetch(apiUrl + "/" + id, {
method: 'PATCH',
body: JSON.stringify({
data
})
}).then((response) => {
response.json().then((response) => {
console.log(response);
})
}).catch(err => {
console.error(err)
})
For DELETE:
function remove(id){
fetch(apiUrl + "/" + id, {
method: 'DELETE'
}).then(() => {
console.log('removed');
}).catch(err => {
console.error(err)
});
For more info visit Using Fetch - Web APIs | MDN https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch > Fetch_API.

Some examples:
async function loadItems() {
try {
let response = await fetch(`https://url/${AppID}`);
let result = await response.json();
return result;
} catch (err) {
}
}
async function addItem(item) {
try {
let response = await fetch("https://url", {
method: "POST",
body: JSON.stringify({
AppId: appId,
Key: item,
Value: item,
someBoolean: false,
}),
headers: {
"Content-Type": "application/json",
},
});
let result = await response.json();
return result;
} catch (err) {
}
}
async function removeItem(id) {
try {
let response = await fetch(`https://url/${id}`, {
method: "DELETE",
});
} catch (err) {
}
}
async function updateItem(item) {
try {
let response = await fetch(`https://url/${item.id}`, {
method: "PUT",
body: JSON.stringify(todo),
headers: {
"Content-Type": "application/json",
},
});
} catch (err) {
}
}

Let me simplify this, you can straight up copy the code.
This is for PUT method :
fetch('https://reqres.in/api/users', + id {
method: 'PUT',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify({
name: 'user'
})
})
.then(res => {
return res.json()
})
.then(data => console.log(data))
and this is for DELETE :
fetch('https://reqres.in/api/users' + id, {
method: 'DELETE',
})
.then(res => {
return res.json()
})
.then(data => console.log(data))
Note: I'm using dummy api here.

This is what worked for me when using the PUT method. This method allows me to effectively update the 1st item using my first name:
fetch('https://reqres.in/api/users', {
method: 'PUT',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify({
id: 1,
first_name: 'Anthony'
})
})
.then(res => {
return res.json()
})
.then(data => console.log(data))

Here are examples for Delete and Put for React & redux & ReduxThunk with Firebase:
Update (PUT):
export const updateProduct = (id, title, description, imageUrl) => {
await fetch(`https://FirebaseProjectName.firebaseio.com/products/${id}.json`, {
method: "PATCH",
header: {
"Content-Type": "application/json",
},
body: JSON.stringify({
title,
description,
imageUrl,
}),
});
dispatch({
type: "UPDATE_PRODUCT",
pid: id,
productData: {
title,
description,
imageUrl,
},
});
};
};
Delete:
export const deleteProduct = (ProductId) => {
return async (dispatch) => {
await fetch(
`https://FirebaseProjectName.firebaseio.com/products/${ProductId}.json`,
{
method: "DELETE",
}
);
dispatch({
type: "DELETE_PRODUCT",
pid: ProductId,
});
};
};

const DeleteBtn = (id) => {
fetch(`http://localhost:8000/blogs/${id}`, {
method: "DELETE"
})
.then(() => {
navigate('/');
});
}
<button onClick={(event) => { DeleteBtn(blog.id)} }>delete</button>