showing success and error messages in react/redux app - reactjs

Question

I'm trying to add toast notifications to my app, one plugin I've been trying to use is react-toastify.
The issue I'm having is probably more a general react/redux issue more than with a plugin such as react-toastify.
I'm using a reducer to set the redux state for errors and success messages, from what I understand with the current code, each error or success message is persistent in the store until another action is called to clear them.
The issue I can't figure out is how do I trigger a toast only once. Eg. I enter the wrong credentials, it creates an error toast, but whenever the state changes and reloads (typing anything into the email or password fields) it creates another toast.
How do I get it to only show once?
userActions.js
function handleErrors(res) {
if (res.ok) {
return res.json();
} else {
return res.json().then(err => {throw err;});
}
}
export const login = (user) => dispatch => {
fetch(`${url}/login`,
{
credentials: 'include',
method: 'post',
body: user,
headers: new Headers({
'Content-Type': 'application/json',
'Accept': 'application/json'
})
})
.then(handleErrors)
.then(res =>
dispatch({
type: LOGIN,
payload: res
})
)
.catch(error =>
dispatch({
type: ERROR,
payload: error
})
)
}
userReducer.js
const initialState = {
errors: '',
success: ''
};
export default function(state = initialState, action) {
switch (action.type) {
case LOGIN:
return {
...state,
errors: '',
success: action.payload.message
};
case ERROR:
return {
...state,
success: '',
errors: action.payload.message
}
default:
return state;
}
}
app.js
app.post('/login', function(req, res) {
... return res.status(500).send({ message: 'Wrong credentials' });
... return res.status(200).send({ message: 'good!' });
});
login.js
class Login extends React.Component {
constructor() {
super();
this.state = {
email: "",
password: ""
}
}
handleChange = event => {
this.setState({
[event.target.id]: event.target.value
});
}
render() {
const { errors, login, success } = this.props;
if (success !== '') toast.success(success, {
position: toast.POSITION.TOP_CENTER
});
if (errors !== '') toast.error(errors, {
position: toast.POSITION.TOP_CENTER
});
return (
<div>
<input type="text" id="email" placeholder="Email Address" onChange={this.handleChange} />
<input type="password" id="password" placeholder="Password" onChange={this.handleChange} />
<button onClick={() => login(JSON.stringify({email: this.state.email, password: this.state.password}))}>Log In</button>
<ToastContainer />
</div>
)
}
}
const mapStateToProps = state => ({
errors: state.store.errors,
success: state.store.success
});
export default connect(mapStateToProps, {login})(Login);

Answer 1

You're calling toast.success or toast.error inside render which makes a new toast pop up every time you re-render the component.
The solution is simple. Move your toast calls outside render, where they will only be called once.
One way to achieve this is to return a value from your userAction.
export const login = (user) => dispatch => {
return new Promise((resolve, reject) => {
fetch(`${url}/login`,
{
credentials: 'include',
method: 'post',
body: user,
headers: new Headers({
'Content-Type': 'application/json',
'Accept': 'application/json'
})
})
.then(handleErrors)
.then(res => {
dispatch({
type: LOGIN,
payload: res
})
resolve(res)
}
)
.catch(error => {
dispatch({
type: ERROR,
payload: error
})
reject(error)
}
)
}
}
Then use that value to toast in login.js.
class Login ... {
...
loginUser = () => {
this.props.login(JSON.stringify({email: this.state.email, password: this.state.password}))
.then(res => {
toast.success(res.message, { position: toast.POSITION.TOP_CENTER })
}
).catch(error => {
toast.error(error.message, { position: toast.POSITION.TOP_CENTER })
}
)
}
...
render() {
return (
...
<button onClick={this.loginUser}>Log In</button>
...
)
}
}
There are other ways to achieve the same functionality and depending on the structure of your project, you may want to toast in a more generalized way.