I have a situation where I should get a song item by id to get the path for that song, and then navigate to that song on button click.
Is there any specific hook that can be used to navigate on data arrival, useEffect will be called any time that state changes but the problem is that first needs to be dispatched the action to get the song, check if it returns any item and then navigate. Typically if it is has been published on the list, it should exist on the db, but the problem might be at the API side, so that check results.length > 0 is why that check is necessary.
useEffect(() => {
const handleClick = (myId: string) => {
dispatch(SongActions.searchSong(myId));
if (results.length > 0) {
if (Object.keys(results[0]).length > 0) {
// navigate(`/songs/${results[0].myPath}`);
}
}
}
}, [dispatch, results])
When user clicks on list item which has a song title, it should call the function handleClick(id) with id of the song as parameter, that is to get the metadata of the song, src path etc.
<Typography onClick={() => handleClick(songItem.songId)} sx={styles.songListItemText}>{songItem.Title}</Typography>
Edit
And this is how I have setup the searchSong action:
searchSong: (obj: SearchSongInputModel): AppThunk<SearchPayload> => async (dispatch) => {
dispatch({
payload: { isLoading: true },
type: SearchActionType.REQUEST,
});
try {
const response = await SearchApi.searchSongAsync(obj);
if (response.length === 0) {
toast.info(`No data found: ${obj.SongId}`)
}
dispatch({
type: SearchActionType.RECEIVED_SONG,
payload: { results: response },
});
} catch (e) {
console.error("Error: ", e);
}
}
You appear to be mixing up the purpose of the useEffect hook and asynchronous event handlers like button element's onClick handlers. The useEffect hook is to meant to issue intentional side-effects in response to some dependency value updating and is tied to the React component lifecycle, while onClick handlers/etc are meant to respond to asynchronous events, i.e. a user clicking a button. They don't mix.
Assuming SongActions.searchSong is an asynchronous action, you've correctly setup Redux middleware to handle them (i.e. Thunks), and the action returns the fetched response data, then the dispatched action returns a Promise that the callback can wait for.
Example:
const navigate = useNavigate();
const dispatch = useDispatch();
const handleClick = async (myId: string) => {
const results = await dispatch(SongActions.searchSong(myId));
if (results.length > 0 && Object.keys(results[0]).length > 0) {
navigate(`/songs/${results[0].myPath}`);
}
};
...
<Typography
onClick={() => handleClick(songItem.songId)}
sx={styles.songListItemText}
>
{songItem.Title}
</Typography>
The searchSong action creator should return a resolved value for consumers to await for.
searchSong: (obj: SearchSongInputModel): AppThunk<SearchPayload> => async (dispatch) => {
dispatch(startRequest());
try {
const results = await SearchApi.searchSongAsync(obj);
if (!results.length) {
toast.info(`No data found: ${obj.SongId}`)
}
dispatch(receivedSong({ results }));
return results; // <-- return resolved value here
} catch (e) {
console.error("Error: ", e);
} finally {
dispatch(completeRequest());
}
}
You can create a state such as const [isDataPresent, setIsDataPresent] = useState(false) to keep track of if the data has arrived or not. And as David has mentioned in the comments you cannot call the function inside the useEffect on handleClick. Instead what you can do is create that function outside the useEffect hook and inside the same function you fetch the data and check if the data is at all present, if present then you can set the above boolean state to true and then redirect from that function itself.
Since you are already fetching the data from the same API and different endpoint, what you can do is -
Create a new component.
Since you are mapping over the data send the data to this component by rendering it inside the map function. It'd allow the data to be passed and components to be rendered one by one.
Create a state in the new component.
Use useEffect hook to fetch the data for a single song since when you are passing the data from the previous component to this one you would also get access to the ID and store it inside the state. This would be occurring inside the newly created component.
Related
I have two actions TEST and TEST_DONE which both increment an id property in my redux state. I am using redux-saga to dispatch the second action TEST_DONE automatically whenever I dispatch the first action TEST from my component.
I expect the order of execution to go like this:
component renders with initial value of testState.id = 0
component dispatches TEST action
component re-renders with testState.id = 1
saga dispatches the TEST_DONE action
component re-renders with testState.id = 2
Instead my component only re-renders when testState.id is updated to 2. I can't see the 1 value in the getSnapshotBeforeUpdate function. It shows 0 as the previous prop.
Why does the prop jump from 0 to 2 without receiving 1 in between?
saga.js:
export function* TestSagaFunc() {
yield put({
type: actions.TEST_DONE
});
};
export default function* rootSaga() {
yield all([
yield takeEvery(actions.TEST, TestSagaFunc),
]);
};
action.js:
const actions = {
TEST: 'TEST',
TEST_DONE: 'TEST_DONE',
callTest: (id) => ({
type: actions.TEST,
payload: {
id
}
}),
};
export default actions;
reducer.js:
const initState = {
testState: {
id: 0
}
};
export default function TestReducers ( state=initState, { type, ...action}) {
switch(type) {
default:
return state;
case actions.TEST: {
const { id } = state.testState;
const nextId = id + 1;
return {
...state,
testState: {
...state.testState,
id: nextId
}
};
};
case actions.TEST_DONE: {
const { id } = state.testState;
const nextId = id + 1;
return {
...state,
testState: {
...state.testState,
id: nextId
}
};
}
};
};
console output from component getSnapshotBeforeUpdate
Summarizing my comments from the question:
The redux state is indeed being updated as you've seen, but a component is not guaranteed to render every intermediate state change based on the way react batches state changes. To test this you can try importing delay from redux-saga/effects and adding yield delay(1000); before calling yield put in TestSagaFunc so the two state updates don't get batched together.
This is just a trick to illustrate the effects of batching and almost certainly not what you want to do. If you need the intermediate state to be rendered you could dispatch TEST_DONE from the component being rendered with a useEffect (or componentDidUpdate) to ensure that the component went through one render cycle with the intermediate state. But there is no way to force your component to render intermediate reducer states that are batched together.
after running mutation using the graphql, if I quickly goback to Previous page,
occur error : Warning: Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and
asynchronous tasks in %s.%s, a useEffect cleanup function,
I think it's because I quickly go to another page during the mutation.
If this is not the case, there is no error.
(Even if an error occurs, update succeeds. but I'm worried about errors)
Even if move to another page during mutating, I want to proceed with the update as it is
How can I proceed with the update?
if If there is no way, is there method that How to create a delay during mutating
im so sorry. my english is not good.
const CalendarTodo = ({
month,
day,
data,`enter code here`
isImportWhether,
setIsImportWhether
}) => {
const [value, setValue] = useState("");
const monthDay = `${month + 1}월 ${day}일`;
const [createToDoMutation] = useMutation(CREATE_TODO, {
variables: {
toDoId:
data &&
data.toDos &&
data.toDos.filter(object => object.monthDay === monthDay)[0] &&
data.toDos.filter(object => object.monthDay === monthDay)[0].id,
monthDay: monthDay,
dayToDo: value,
importEvent: isImportWhether
},
update: (proxy, { data: { createToDo } }) => {
const data = proxy.readQuery({ query: SEE_TODO_OF_ME });
data &&
data.toDos &&
data.toDos.filter(object => object.monthDay === monthDay)[0] &&
data.toDos
.filter(object => object.monthDay === monthDay)[0]
.dayToDo.push(createToDo);
proxy.writeQuery({ query: SEE_TODO_OF_ME, data });
},
optimisticResponse: {
createToDo: {
__typename: "DayToDo",
id: Math.random().toString(),
toDoList: value,
importEvent: isImportWhether
}
}
});
return (
<>
);
};
export default CalendarTodo;
As you already guessed the reason is the asynchronous request that keeps on running even after un-mounting the component due to navigating away from it.
There are many ways to solve this. One is to add a check whether or not the component you are calling the async request from is still mounted and only update its state if so, e.g.:
useEffect(() => {
let isMounted = true;
apollo.mutate({query, variables, update: {
if(isMounted) {
// update state or something
}
})
return () => {
isMounted = false;
};
}, []);
This way however the data might be lost. If you want to make sure that you receive and store the return value you should add the request to a higher level component or context hat will not be unmounted on navigation. This way you can trigger the async call but dont have to worry about navigating away.
I have a redux form that will call a rest API on form submission. If the API call fails I'd like to raise a SubmissionError so that the error can be displayed on the form. As the submission error details map to properties on the form I would like this handling to be part of the form component.
Once the form has successfully submitted to the API and got a success response I would like the form component to call a method (methodA) supplied to the form component.
At the moment the only way I can see of doing this is to:
Pass methodA in the props of the form component.
In the form component's call to reduxForm() supply a method to onSubmitSuccess in the config object (methodB)
In methodB pull methodA from the supplied props and then call it
Is this the best way of doing what I want or is there a simpler way?
In the action creator (assuming you are using react-thunk)
const submit = (url, data) => dispatch => {
dispatch({ type: 'submit-start' });
return new Promise((res, rej) =>
fetch(/*do some stuff*/)
.then(res => {
if (res.status !== 200) {
dispatch({ type: 'submit-err' })
//the object which is rejected here
//configures the errors displayed in the form
//in best case your server delivers an appropriate
//response
rej({ _error: 'Validation Failed', age: 'too young' });
} else {
dispatch({ type: 'submit-success' });
res(res.json())
}
})
);
}
export { submit };
and in the component:
submit (data) {
return this.props.submit(<url>, data)
}
render () {
const { handleSubmit } = this.props;
return <form onSubmit={handleSubmit(submit)}>…</form>
}
If the returned Promise from the action creator is rejected, the error message is displayed.
Redux-Thunk returns the return value of the function called with dispatch as parameter, in this case a promise.
For redux form submit validation, the submit function must return a promise, which can be resolved, or rejected.
docs
I recently started migrating things from jQ to a more structured framework being VueJS, and I love it!
Conceptually, Vuex has been a bit of a paradigm shift for me, but I'm confident I know what its all about now, and totally get it! But there exist a few little grey areas, mostly from an implementation standpoint.
This one I feel is good by design, but don't know if it contradicts the Vuex cycle of uni-directional data flow.
Basically, is it considered good practice to return a promise(-like) object from an action? I treat these as async wrappers, with states of failure and the like, so seems like a good fit to return a promise. Contrarily mutators just change things, and are the pure structures within a store/module.
actions in Vuex are asynchronous. The only way to let the calling function (initiator of action) to know that an action is complete - is by returning a Promise and resolving it later.
Here is an example: myAction returns a Promise, makes a http call and resolves or rejects the Promise later - all asynchronously
actions: {
myAction(context, data) {
return new Promise((resolve, reject) => {
// Do something here... lets say, a http call using vue-resource
this.$http("/api/something").then(response => {
// http success, call the mutator and change something in state
resolve(response); // Let the calling function know that http is done. You may send some data back
}, error => {
// http failed, let the calling function know that action did not work out
reject(error);
})
})
}
}
Now, when your Vue component initiates myAction, it will get this Promise object and can know whether it succeeded or not. Here is some sample code for the Vue component:
export default {
mounted: function() {
// This component just got created. Lets fetch some data here using an action
this.$store.dispatch("myAction").then(response => {
console.log("Got some data, now lets show something in this component")
}, error => {
console.error("Got nothing from server. Prompt user to check internet connection and try again")
})
}
}
As you can see above, it is highly beneficial for actions to return a Promise. Otherwise there is no way for the action initiator to know what is happening and when things are stable enough to show something on the user interface.
And a last note regarding mutators - as you rightly pointed out, they are synchronous. They change stuff in the state, and are usually called from actions. There is no need to mix Promises with mutators, as the actions handle that part.
Edit: My views on the Vuex cycle of uni-directional data flow:
If you access data like this.$store.state["your data key"] in your components, then the data flow is uni-directional.
The promise from action is only to let the component know that action is complete.
The component may either take data from promise resolve function in the above example (not uni-directional, therefore not recommended), or directly from $store.state["your data key"] which is unidirectional and follows the vuex data lifecycle.
The above paragraph assumes your mutator uses Vue.set(state, "your data key", http_data), once the http call is completed in your action.
Just for an information on a closed topic:
you don’t have to create a promise, axios returns one itself:
Ref: https://forum.vuejs.org/t/how-to-resolve-a-promise-object-in-a-vuex-action-and-redirect-to-another-route/18254/4
Example:
export const loginForm = ({ commit }, data) => {
return axios
.post('http://localhost:8000/api/login', data)
.then((response) => {
commit('logUserIn', response.data);
})
.catch((error) => {
commit('unAuthorisedUser', { error:error.response.data });
})
}
Another example:
addEmployee({ commit, state }) {
return insertEmployee(state.employee)
.then(result => {
commit('setEmployee', result.data);
return result.data; // resolve
})
.catch(err => {
throw err.response.data; // reject
})
}
Another example with async-await
async getUser({ commit }) {
try {
const currentUser = await axios.get('/user/current')
commit('setUser', currentUser)
return currentUser
} catch (err) {
commit('setUser', null)
throw 'Unable to fetch current user'
}
},
Actions
ADD_PRODUCT : (context,product) => {
return Axios.post(uri, product).then((response) => {
if (response.status === 'success') {
context.commit('SET_PRODUCT',response.data.data)
}
return response.data
});
});
Component
this.$store.dispatch('ADD_PRODUCT',data).then((res) => {
if (res.status === 'success') {
// write your success actions here....
} else {
// write your error actions here...
}
})
TL:DR; return promises from you actions only when necessary, but DRY chaining the same actions.
For a long time I also though that returning actions contradicts the Vuex cycle of uni-directional data flow.
But, there are EDGE CASES where returning a promise from your actions might be "necessary".
Imagine a situation where an action can be triggered from 2 different components, and each handles the failure case differently.
In that case, one would need to pass the caller component as a parameter to set different flags in the store.
Dumb example
Page where the user can edit the username in navbar and in /profile page (which contains the navbar). Both trigger an action "change username", which is asynchronous.
If the promise fails, the page should only display an error in the component the user was trying to change the username from.
Of course it is a dumb example, but I don't see a way to solve this issue without duplicating code and making the same call in 2 different actions.
actions.js
const axios = require('axios');
const types = require('./types');
export const actions = {
GET_CONTENT({commit}){
axios.get(`${URL}`)
.then(doc =>{
const content = doc.data;
commit(types.SET_CONTENT , content);
setTimeout(() =>{
commit(types.IS_LOADING , false);
} , 1000);
}).catch(err =>{
console.log(err);
});
},
}
home.vue
<script>
import {value , onCreated} from "vue-function-api";
import {useState, useStore} from "#u3u/vue-hooks";
export default {
name: 'home',
setup(){
const store = useStore();
const state = {
...useState(["content" , "isLoading"])
};
onCreated(() =>{
store.value.dispatch("GET_CONTENT" );
});
return{
...state,
}
}
};
</script>
I have created APIs with Nodejs/Express.
Let say I can do GET request to localhost:8080/list and it returns JSON of my TODO list and I can POST to localhost:8080/list to create new to do list.
Then I use Riotjs + Riotcontrol for my Frontend website.
How do I request from todostore.js file?
This is the riotcontrol todostore.js file which I get from riotcontrol demo folder
Riotcontrol
// TodoStore definition.
// Flux stores house application logic and state that relate to a specific domain.
// In this case, a list of todo items.
function TodoStore() {
riot.observable(this) // Riot provides our event emitter.
var self = this
self.todos = [
{ title: 'Task 1', done: false },
{ title: 'Task 2', done: false }
]
// Our store's event handlers / API.
// This is where we would use AJAX calls to interface with the server.
// Any number of views can emit actions/events without knowing the specifics of the back-end.
// This store can easily be swapped for another, while the view components remain untouched.
self.on('todo_add', function(newTodo) {
self.todos.push(newTodo)
self.trigger('todos_changed', self.todos)
})
self.on('todo_remove', function() {
self.todos.pop()
self.trigger('todos_changed', self.todos)
})
self.on('todo_init', function() {
self.trigger('todos_changed', self.todos)
})
// The store emits change events to any listening views, so that they may react and redraw themselves.
}
You could do something like this in your TodoStore
self.on('todo_init', function() {
// Trigger loading here perhaps, then set loading = false when it's loaded
//self.trigger('set_loading', {value: true})
fetch('http://localhost:8080/list')
.then(response => response.json())
.then(function (json) {
self.todos = json
self.trigger('todos_changed', self.todos)
})
})