I got this error message
I know lots of questions are there on this error, but in my case, i can't use spread inside mapStateToProps, While in my previous case, I can use spread inside mapStateToProps. can anybody tell me about this error?
this is my code by the way
const mapStateToProps = state => {
const IncomeVal = _.map(state.IncomeVal, (val, uid) => {
return { ...val, uid };
});
return { IncomeVal };
};
export default connect(mapStateToProps, { ValueIncome })(PageHome);
Are you trying to return a props object with the same properties as the state.IncomeVal.val object and also a property for state.IncomeVal.uid? Please try this:
const mapStateToProps = state => ({
...state.IncomeVal.val,
uid: state.IncomeVal.uid
});
Here is a plunkr demonstrating the js spread operator.
Related
I have a FlatList component that uses Redux (indirectly) as the source for the data prop. See below
const mapStateToProps = state => ({
rdx_activeUsers: state.profile.activeUsers,
});
convertRdxActiveUsersObjectToUsableArray = () => {
let activeUsersArray = [];
Object.values(this.props.rdx_activeUsers).forEach(userObj => {
activeUsersArray.push(userObj);
});
return activeUsersArray;
};
//-----------------------------------------------------------------------
render() {
let usableArray4FlatList = this.convertRdxActiveUsersObjectToUsableArray();
return (
<View>
<FlatList
data={usableArray4FlatList}
Whenever an active user is added or removed in Firebase DB, I have listeners that increase or reduce the size of the Redux object rdx_activeUsers.......the goal is that this change in Redux should trigger the render() function (due to Redux being used in the convertRdxActiveUsersToUsableArray function....which is present in the render() function).
I can see via debugging tool that Redux rdx_activeUsers object is updating correctly whenever I add or remove a user....however the FlatList only rerenders dynamically when I add a user (i.e. the Redux object rdx_activeUsers increases in size)...but not when I remove one (i.e the Redux object rdx_activeUsers decreases in size).
I also tried adding prop extraData={this.props.rdx_activeUsers} ...but this didnt make any difference
UPDATE AS OF 12/31
Below are my reducers......
case ACTIVE_USER_CHILD_ADDED is successfully updating Redux AND triggering the rerender
case ACTIVE_USER_CHILD_REMOVED is successfully updating Redux BUT NOT triggering the rerender....looks like thats where the issue is
case ACTIVE_USER_CHILD_ADDED:
const key2Add = action.payload.userId;
const val2Add = action.payload;
return { ...state, activeUsers: { ...state.activeUsers, [key2Add]: val2Add } };
case ACTIVE_USER_CHILD_CHANGED:
const key2Updel = action.payload.userId;
const val2Updel = action.payload;
if (val2Updel.active) {
return { ...state, activeUsers: { ...state.activeUsers,[key2Updel]: val2Updel } };
}
if (state.activeUsers) {
const updatedstate = state;
delete updatedstate.activeUsers[key2Updel];
return {...updatedstate};
}
//else
return state;
case ACTIVE_USER_CHILD_REMOVED:
const key2Del = action.payload.userId;
const oldState = state;
delete oldState.activeMsgUsers[key2Del];
return {...oldState};
Below shows my action creators
export const _actActiveUserChildAdded = userObj => {
return {
type: ACTIVE_USER_CHILD_ADDED,
payload: userObj,
};
};
export const _actActiveUserChildChanged = userObj => {
return {
type: ACTIVE_USER_CHILD_CHANGED,
payload: userObj,
};
};
export const _actActiveUserChildRemoved = userObj => {
return {
type: ACTIVE_USER_CHILD_REMOVED,
payload: userObj,
};
};
change case ACTIVE_USER_CHILD_REMOVED like following it should work, you are modifying the object which was mutating the state object instead of returning a new object.
case ACTIVE_USER_CHILD_REMOVED:
const key2Del = action.payload.userId;
const {activeUsers:{[key2Del]:_,...restActiveUsers}} = state;
return {...state,activeUsers:{...restActiveUsers}};
This piece of code does not trigger a rerender
case ACTIVE_USER_CHILD_REMOVED:
const key2Del = action.payload.userId;
const oldState = state;
delete oldState.activeMsgUsers[key2Del];
return {...oldState};
By returning {...oldState} all the references inside this.state stay the same, and no update is triggered
fast solution
Put return {...oldState, activeMsgUsers: {...activeMsgUsers}} instead
better solution
Don't use delete, use Array.filter instead to create a new object reference
best solution
Refactor your conponent to hooks and make activeMsgUsers a standalone state, if you do it correctly, calling setActiveMsgUsers returning the destructured old state you cannot have that problem
try this
const mapStateToProps = state => ({
rdx_activeUsers: state.profile.activeUsers,
});
//-----------------------------------------------------------------------
render() {
let activeUsersArray = [];
Object.values(this.props.rdx_activeUsers).forEach(userObj => {
activeUsersArray.push(userObj);
});
return (
<View>
<FlatList
data={activeUsersArray}
this is my code :
export const state = () => ({
products: []
});
export const getters = {
getProducts: state => {
return state.products;
}
};
export const mutations = {
SET_IP: (state, payload) => {
state.products = payload;
}
};
export const actions = () => ({
async getIP({ commit }) {
const ip = await this.$axios.$get("http://localhost:8080/products");
commit("SET_IP", ip);
}
});
the server is working nicely but i just can't get the data into the store
First of all, I highly recommend you rename your action and mutation to something like getProducts and SET_PRODUCTS instead of ip. Also make sure you change the variable name inside the action. While this doesn't change any functionality, it makes your code easier to read.
Second, maybe add a console.log(ip) right after you define the const in the action and see if you're getting the data you want in there. In most cases you're going to want to assign ip.data to your variable.
Lastly, make sure you're calling the action somewhere in the code.
You should do it like this:
this.$store.dispatch('getIP'); // Using your current name
this.$store.dispatch('getProducts'); // Using my recommended name
I'm new to hooks and ran across this setup on SO and wanted to confirm that this is the correct pattern. I was getting the RN "unmounted component" leak warning message before and this seemed to solve it. I'm trying to mimic in some way compnentDidMount. This is part of a phone number verify sign up flow and onMount I want to just check for navigation and then fire off a side effect, set mounted true and then unmount correctly.
const SMSVerifyEnterPinScreen = ({ route, navigation }) => {
const [didMount, setDidMount] = useState(false)
const { phoneNumber } = route.params
useEffect(() => {
if(navigation) {
signInWithPhoneNumber(phoneNumber)
setDidMount(true)
}
return () => setDidMount(false)
}, [])
if (!didMount) { return null }
async function signInWithPhoneNumber(phoneNumber) {
const confirmation = await auth().signInWithPhoneNumber('+1'+phoneNumber)
...
}
return (
...
)
}
RN 0.62.2 with react-nav 5 - thanks!
Since signInWithPhoneNumber is a async function and will setState you will see warning it the component is unmounted before the response is available
In order to handle such scenarios you can keep a variable to keep track whether its mounted or not and then only set state is the mounted variable is true
However you do not need to return null if component has unmounted since that doesn't accomplish anything. The component is removed from view and will anyways not render anything.
Also you do not need to maintain this value in state, instead use a ref
const SMSVerifyEnterPinScreen = ({ route, navigation }) => {
const isMounted = useRef(true)
const { phoneNumber } = route.params
useEffect(() => {
if(navigation) {
signInWithPhoneNumber(phoneNumber)
}
return () => {isMounted.current = false;}
}, [])
async function signInWithPhoneNumber(phoneNumber) {
const confirmation = await auth().signInWithPhoneNumber('+1'+phoneNumber)
...
}
return (
...
)
}
I have a custom reducer and a connected component to change its state. Now I'd like to use this state as a permanent filter on List elements.
I understand the List elements are connected to the redux-state, so I hope I'm able to access it through the List component's props, but couldn't find a way how to do that.
The List component is connected but not yours.
import { connect } from "react-redux";
const MyList = ({ is_published, ...props }) => (
<List {...props} filter={{ is_published }}>
</List>
);
const mapStateToProps = state => ({
is_published: state.myCustomReducer.is_published,
});
export default connect(mapStateToProps, undefined)(MyList);
Edit:
Just found out we don't update data when this prop change. This is a bug and you can open an issue about it.
In the mean time, here's a workaround:
Create a custom saga listening to whatever action you use alongside your custom reducer (I'll call it SET_IS_PUBLISHED for my example). This custom saga should put the changeListParams action creator from react-admin with your filter.
It will probably looks like this (not tested):
import { takeEvery, put, select } from 'redux-saga/effects'
import { changeListParams } from 'react-admin'
import { SET_IS_PUBLISHED } from './isPublished'
const getCurrentListParams = (state, resource) => {
const resourceState = state.admin.resources[resource]
return resourceState.list.params
}
function handleSetPublished({ payload }) {
const currentParams = yield select(getCurrentListParams)
const newParams = {
// Keep the current params
...currentParams,
// Override the filter
filter: {
// Keep the current filter
...currentParams.filter,
// Only override the is_published
is_published: payload
}
}
// Dispatch the action for the `posts` resource
yield put(changeListParams('posts', newParams))
}
export default function* () {
yield takeEvery(SET_IS_PUBLISHED, handleSetPublished)
}
just to bring this into 2021, you can use the useSelector redux hook to get hold of your custom state:
import { useSelector } from 'react-redux';
const MyCustomThing = (props) => {
const is_published = useSelector(state => state.customState.is_published);
}
For completeness, react-admin provides a customReducers prop to its <Admin> component so you can extend the redux state with your custom values:
const customStateReducer = (customState = { is_published: false }, { type, payload }) => {
if (type === 'IS_PUBLISHED') customState.is_published = payload.is_published;
return customState;
}
<Admin customReducers={{ customState: customStateReducer }} ...>
etc
I am quite new to JavaScript and react-native and I have existing project that I need to add functionality to. It is using redux and redux-thunk with redux-saga to send API requests. Currently it supports only 1 dispatch function per component and I need to dispatch several types of requests to the saga. I am trying to bindActionCreators to add the dispatch to the stores but to no avail.. I am totally lost on the mapDispatchToProps part and how do I "fire the action" afterwards..
in single dispatch to props, I did this:
let sdtp = (arg) => {
return (dispatch) => {
dispatch({
type: 'GET_TEST_HASHMAP_SAGA',
hashmap: arg
})
}
}
export default MainPage = connect(
mapStateToProps,
{ sdtp }
)(MainPage);
and I can "access the function" (is this the right term? at least my saga gets called) inside the MainPage.render() component :
`this.props.sdtp({'hello':'world'});`
but when I change to use bindActionCreators, I cannot access it in the props anymore (I have tried so many different experiments I almost give up)
Here is how I construct my multiple dispatches:
let action1 = (args) => {
return (dispatch) => {
dispatch({
type: 'GET_TEST_HASHMAP_SAGA',
hashmap: arg
});
}
}
let action2 = (args) => {
return (dispatch) => {
dispatch({
type: 'GET_TEST_HASHMAP_SAGA2',
params: arg
});
}
}
let action3 = (args) => {
return (dispatch) => {
dispatch({
type: 'GET_TEST_HASHMAP_SAGA3',
args: arg
});
}
}
let mdtp = (dispatch) => {
return {
actions: bindActionCreators(action1, action2, action3, dispatch)
}
}
export default MainPage = connect(
mapStateToProps,
{ mdtp }
)(MainPage);
I am trying to access the actions like this:
this.props.mdtp.action1({arg: 'hello'});
Thanks in advance!
connect takes four arguments...most people usually only need the first two.
mapStateToProps you have, and I'm assuming it's a function.
mapDispatchToProps is the second...the issue is there.
bindActionCreators is nothing but a for loop...leave it out and you will better understand what is happening.
Try this:
function mapDispatchToProps(dispatch) {
return {
action1: (args) => dispatch(action1(args)),
action2: (args) => dispatch(action2(args)),
}
}
export default MainPageContainer = connect(
mapStateToProps,
mapDispatchToProps
)(MainPage)
And call them as
this.props.action1(args) and this.props.action2(args)
If you insist on using the overrated bindActionCreators the syntax would be:
function mapDispatchToProps(dispatch){
return {
actions: bindActionCreators({
action1,
action2,
}, dispatch)
}
}
Also, use const instead of let since you are not redefining the value. It is also best to export the connected component under a different name than the class name of the component.
In your mpdt function, you need to return result of bindActionCreators call, not object with action key.
So, it should be
const mdtp = (dispatch) => {
return bindActionCreators({
action1, action2, action3
}, dispatch);
};
and you can call them as this.props.action1(...)
From your code it also seems, that you have confused two ways of passing action creators to the component. One way is described above. And another way, you can pass your action creators directly to connect() using object notations, like so
export default MainPage = connect(
mapStateToProps,
{ action1, action2, action3 }
)(MainPage);
which will have same result. And your first approach, with sdtp action creator uses this approach.
Alternatively, you can also skip mapDispatchToProps entirely..
Within your render() function, you can just call dispatch directly like this:
this.props.dispatch({type: 'GET_TEST_HASHMAP_SAGA2', params: {"hello": "world"}});
Then in your connect function, you can skip the mapDispatchToProps param entirely.
export default MainPage = connect(
mapStateToProps
)(MainPage);
I know this isn't the answer, but this is just an alternative that works as well