i m using Vue3 and Vuex, here is the version.
"vue": "^3.0.5",
"vuex": "^4.0.0",
I was trying to reset the state in a module by using the default state. But I found either I assign the state equal to the return value of the getDefault function or destructure the state and return value, the state and this._state shows a different value. the value in this._state still shows the previous value (did not get updated).
However, if I use the way that I commented in the resetState, the value of state and this._state are the same.
I would like to know why are the results different by using different ways to reset the state.
Here is the code:
const getDefaultState = () => {
return {
vueInstances: {},
};
};
export default {
namespaced: 'test',
state: getDefaultState(),
mutations: {
resetState(state) {
// const newState = getDefaultState();
// for (const stateField in newState) {
// if (newState.hasOwnProperty(stateField)) {
// state[stateField] = newState[stateField];
// }
// }
state = getDefaultState() // state = [...state, ...getDefaultState()]
console.log(state);
console.log(this._state);
},
addVueInstance(state, payload) {
state.vueInstances = {
...state.vueInstances,
[payload.name]: payload.instance,
};
},
},
actions: {
addVueInstance({ commit, state }, payload) {
if (state[payload.name]) {
return;
}
commit('addVueInstance', payload);
},
},
};
here is result
// console.log(state)
{
"vueInstances": {}
}
// console.log(this._state)
{
vueInstances:{
clientPopup: {_uid: 0, _component: {…}, _props: null, …}
}
}
Related
All the examples show that the initial state is an object. Can I put an array or a string into the state?
{
state: [], // just an array or string
mutations: {
add(state, { name }) {
return [...state, { name }];
}
},
actions: { ... },
getters: { ... }
}
This way I won't be able to set properties on the state, instead just return the current state inside a mutation
Getter is returning empty value in observer. But the state is setting properly in the mutation.
Not able to check in Vuex dev tools in console as it says "No Store Detected". I've checked it by logging it in console
Vue File :
computed: {
...mapGetters('listings', ['listingContracts']),
},
methods: {
...mapActions('listings', [
'productBasedListings',
]),
},
onChange(product) {
this.productBasedListings( product.id );
console.log('LIST:', this.listingContracts); // Empty in observer
},
Store :
state: {
contracts: [],
},
getters: {
listingContracts(state) {
console.log('GETTER', state.contracts); // Empty in observer
return state.contracts;
},
},
mutations: {
setListing(state, { lists }) {
state.contracts = lists;
console.log('AFTER MUTATION:', state.contracts); // Setting the value properly
},
},
actions: {
async productBasedListings({ commit }, { id, state }) {
let listing = [];
try {
listing = await publicApi.listings(id);
console.log('ACTION:', listing);
commit({
lists: listing,
type: 'setListing',
});
} catch (e) {
console.error(`Failed to change #${id} state to #${state}:\t`, e);
throw e;
}
},
}
Here "Getter" does not have any values but "After Mutation" we have the values.
Because initially the store variable is empty.The values are itself set in the mutation.Hence showing up after mutation is called.
Well now to get data after mutation is fired use async await in your method as below:
async onChange(product) {
await this.productBasedListings( product.id ).then(() => {
console.log('LIST:', this.listingContracts);
})
},
I have a simple VueJS SPA served by Express. Express also handles API endpoints called by Vue front-end.
Express is connected to Postgres, and API endpoints interact with the database (perform basic CRUD operations).
In my database, I have a single "patient" table, with columns "first_name", "last_name", "date_of_birth", and "id".
In the created() hook of PatientList.vue component, database is queried for all patients, and this information is saved to component data, displayed using v-for loop.
My PatientList.vue code is:
<script>
import auth from '#/auth/authenticator';
import { mapMutations } from 'vuex';
export default {
components: {
name: 'PatientsList',
},
data() {
return {
patients: [],
}
},
computed: {
accessTokenGetter: {
get: function () {
return this.$store.getters.accessToken;
},
},
patientEditStatusGetter: {
get: function () {
return this.$store.getters.g_patientEditStatusCheck;
},
},
},
methods: {
...mapMutations([
'm_startPatientEditProcess',
'm_endPatientEditProcess',
'm_clearPatientEditState',
'm_cachePatient'
]),
cachePatientHandler(ptnt) {
console.log('PatientList.vue method cachePatientHandler', ptnt);
var patientObject = {
'date_of_birth': ptnt.date_of_birth.split('T')[0],
'first_name': ptnt.first_name,
'last_name': ptnt.last_name,
'patient': ptnt.patient,
'uid': ptnt.uid
}
this.m_endPatientEditProcess(false);
this.m_clearPatientEditState('');
this.m_startPatientEditProcess(true);
this.m_cachePatient(patientObject);
},
getPatients() {
const xhr = new XMLHttpRequest();
xhr.open('GET', 'https://voyager.wrk.health/patients/index');
xhr.setRequestHeader('Authorization', `Bearer ${this.accessTokenGetter}`);
xhr.setRequestHeader('Cache-control', 'no-cache');
xhr.onload = () => {
var data = JSON.parse(xhr.response);
for( var i=0, r = data.results; i<r.length; i++ ){
this.patients.push(r[i]);
}
};
xhr.onerror = () => {
console.log(xhr.statusText);
};
xhr.send();
},
},
beforeCreate() {
},
created() {
console.log('PatientList.vue created()');
if(auth.isUserLogged()){
this.getPatients();
} else {
router.go('/');
}
},
};
</script>
In order to edit a patient, I have router-link to edit page. Router-link has click-handler, argument passed in is iterable from v-for loop (i.e. single patient object). I have 4 mutations related to this
const mutations = {
m_startPatientEditProcess(state, trueStatus) {
console.log('Vuex patient m_startPatientEditProcess');
state.patientEditStatus = trueStatus;
},
m_endPatientEditProcess(state, falseStatus) {
console.log('Vuex patient m_endPatientEditProcess');
state.patientEditStatus = falseStatus;
},
m_clearPatientEditState(state, emptyString) {
console.log('Vuex patient m_clearPatientEditState');
state.patientDetails.date_of_birth = emptyString;
state.patientDetails.first_name = emptyString;
state.patientDetails.last_name = emptyString;
state.patientDetails.patient = emptyString;
state.patientDetails.uid = emptyString;
},
m_cachePatient(state, patientObj) {
console.log('Vuex patient m_cachePatient, received: ', patientObj);
state.patientDetails.date_of_birth = patientObj.date_of_birth;
state.patientDetails.first_name = patientObj.first_name;
state.patientDetails.last_name = patientObj.last_name;
state.patientDetails.patient = patientObj.patient;
state.patientDetails.uid = patientObj.uid;
},
Also, my PatientEdit.vue code is:
<script>
import { mapMutations } from 'vuex';
export default {
components: {
name: 'PatientEdit',
},
data() {
return {
patientToEdit: {
first_name: '',
last_name: '',
date_of_birth: '',
patient: '',
uid: '',
},
patientDetailsLoaded: false,
}
},
computed: {
patientToEditDetailsGetter: {
get: function() {
return this.$store.getters.g_patientToEditDetails;
}
},
accessTokenGetter: {
get: function() {
return this.$store.getters.accessToken;
}
}
},
methods: {
...mapMutations([
'm_endPatientEditProcess',
'm_clearPatientEditState',
]),
populatePatientEditState() {
const pDeets = this.patientToEditDetailsGetter;
this.patientToEdit.first_name = pDeets.first_name;
this.patientToEdit.last_name = pDeets.last_name;
this.patientToEdit.date_of_birth = pDeets.date_of_birth;
this.patientToEdit.patient = pDeets.patient;
this.patientToEdit.uid = pDeets.uid;
this.patientDetailsLoaded = true;
},
submitUpdatedPatientDetails() {
const payload = Object.assign({}, this.patientToEdit);
const xhr = new XMLHttpRequest();
xhr.open('PUT', `https://voyager.wrk.health/patients/update/${payload.uid}`)
xhr.setRequestHeader('Content-type', 'application/json');
xhr.setRequestHeader('Authorization', `Bearer ${this.accessTokenGetter}`);
xhr.onload = async () => {
try {
await console.log(xhr.response);
await console.log('Sent patient data to update endpoint \n Ready to be redirected.');
await Promise.all([this.m_endPatientEditProcess(false), this.m_clearPatientEditState('')]);
await this.$router.push('/patients/index');
} catch (e) {
throw new Error(e);
}
}
xhr.send(JSON.stringify(payload));
}
},
created() {
this.populatePatientEditState();
},
};
</script>
My reasoning was to avoid unnecessary request to database.
Everything works as intended. I have a store.subscription set up to save Vuex state to localStorage (for session persistence when this application is refreshed).
Store subscription logs state and mutation, everything is normal like so:
First store output
If I open a new tab or window (cookies left untouched), and try to perform the same update operations, my store subscription freaks out, and I cannot auto-populate my PatientEdit page with patient information from Vuex.
According to the output, suddenly mutation is committing things that I never specified like so:
Store output 2
Why does this happen?
Thanks for reading.
NB: If I have missed information necessary to figure this behaviour out, please let me know.
Edit 1:
Vuex store:
import Vue from 'vue';
import Vuex from 'vuex';
import session from './modules/session';
import patient from './modules/patient';
Vue.use(Vuex);
const store = new Vuex.Store({
modules: {
session,
patient,
},
mutations: {
initStore(state) {
console.log('Vuex root state checking for local snapshot');
if (localStorage.getItem('store')) {
console.log('Snapshot found, hydrating...');
this.replaceState(Object.assign(store, JSON.parse(localStorage.getItem('store'))));
}
},
},
});
store.commit('initStore');
store.subscribe((mutation, state) => {
console.warn('Subscription detected');
console.log('mutation: ', mutation);
console.log('state: ', state);
localStorage.setItem('store', JSON.stringify(state));
});
export default store;
You end up with a "cannot stringify circular JSON" error, because you are turning the state, but also the getters, mutations and actions into a string. These contain references to the object you are trying to stringify, which results in an infinite loop.
This is not a problem in your first run, because your localStorage is still empty then. You correctly stringify your state, but when you reload the following line runs:
this.replaceState(Object.assign(store, JSON.parse(localStorage.getItem('store'))));
This line replaces your state with your store, extended with what you have in localStorage. If you replace store with state things should work much better.
I am creating an app and I have a component "Message" which uses a store to get data back from a JSON file (this will be eventually a database) and the component is as follows:
export default {
props: ['message'],
mounted: function() {
this.$store.dispatch("FETCHMESSAGE", this.message);
},
computed: {
title: function() {
return this.$store.state.message;
}
}
}
I have the following mutation:
FETCHMESSAGE: function (context, type)
{
var data = json.type; // Get the data depending on the type passed in
// COMMIT THE DATA INTO THE STORE
}
And I use it as the following:
<MessageApp message="welcome"></MessageApp>
This works for the most part and the correct message is displayed. The issue is when I have multiple instances of MessageApp being called on the same page. They both show the same message (of the last message) being called. E.g.
<MessageApp message="welcome"></MessageApp>
<MessageApp message="goodbye"></MessageApp>
They will each show the goodbye message. I know why this is happening but is it possible to have multiple instances of the store so that this does not happen?
Vuex is "a centralized store for all the components in an application," as the docs say.
So imagine that you have a variable (or many) which you can use and change from all your components.
Also when you want to get properties from state, it is recommended to use getters.
I can't understand what you want to do, but if you want, you can have multiple states, getters, mutations and actions and use them as modules in the store (read more). See below example from Vuex docs:
const moduleA = {
state: { title: '' },
mutations: { changeTitle(state, payload) { state.title = payload } },
actions: { changeTitle({commit}, payload) { commit('changeTitle', payload) } },
getters: { getTitle(state) { return state.title } }
}
const moduleB = {
state: { title: '' },
mutations: { changeTitle(state, payload) { state.title = payload } },
actions: { changeTitle({commit}, payload) { commit('changeTitle', payload) } },
getters: { getTitle(state) { return state.title } }
}
const store = new Vuex.Store({
modules: {
a: moduleA,
b: moduleB
}
})
store.state.a // -> `moduleA`'s state
store.state.b // -> `moduleB`'s state
I am running ESLint and I am currently running into the following ESLint error:
error 'state' is already declared in the upper scope no-shadow
const state = {
date: '',
show: false
};
const getters = {
date: state => state.date,
show: state => state.show
};
const mutations = {
updateDate(state, payload) {
state.date = payload.date;
},
showDatePicker(state) {
state.show = true;
}
};
export default {
state,
getters,
mutations
};
What would be the best way to fix this?
The best way to fix would be to read the docs about the eslint "no-shadow" rule.
From this documentation, the best solution would probably be to include an exception for this one variable with the "allow" option.
You can add this with a comment to the js file to keep the exeption local:
/* eslint no-shadow: ["error", { "allow": ["state"] }]*/
The best solution is #Linus Borg's answer.
If you are looking for an alternative, you can declare the state constant below the rest. This will prevent variable shadowing because state will not be declared in the outer-scope yet.
Example:
const getters = {
date: state => state.date,
show: state => state.show
};
const mutations = {
updateDate(state, payload) {
state.date = payload.date;
},
showDatePicker(state) {
state.show = true;
}
};
const state = {
date: '',
show: false
};
export default {
state,
getters,
mutations
};
If it's not too late
const data = {
date: '',
show: false
};
const getters = {
date: state => state.date,
show: state => state.show
};
const mutations = {
updateDate(state, payload) {
state.date = payload.date;
},
showDatePicker(state) {
state.show = true;
}
};
export default {
state: data,
getters,
mutations
};
basically you define your store data as data, and you export it as state state: data
Had the same issue as I was using an airbnb eslint config which is incompatible with vuex.
This worked for me, after restarting dev environment.
I created a new .eslintrc.js file in my store folder and added them there
"no-shadow": ["error", { "allow": ["state"] }],
"no-param-reassign": [
"error",
{
"props": true,
"ignorePropertyModificationsFor": [ // All properties except state are in the ignorePropertyModificationsFor array by default.
"state",
"acc",
"e",
"ctx",
"req",
"request",
"res",
"response",
"$scope"
]
}
],
Based on #allochi's answer, this is what I had to do to make it work With Vue 3 which uses Vuex 4 which prefers returning a function for state:
// store.js
const data = {
// ...
};
const getters = {
// ...
};
const mutations = {
// ...
};
const actions = {
// ...
};
export default {
state() { return data; },
getters,
mutations,
actions
};
If you need to import particular functions from outside, you will have to do it like this:
import mystore from './mystore';
const Store = createStore({
state: mystore.state,
getters: mystore.getters,
mutations: mystore.mutations,
actions: mystore.actions
});
I would only recommend this though if you really can't use /* eslint no-shadow: ["error", { "allow": ["state"] }]*/