I dont know why, but my computed property is not firing when state changes.
I am dispatching actions and as a result state changes. but data is not firing at all. wanna help :(
//store
mutations: {
setStudyData(state, payload) {
state.studyData = [...payload];
},
},
actions: {
async postLogin({ state, commit, dispatch }, { userId, userPass }) {
try {
const res = await axios.post(`${url}/v1/api/user/auth/signin`, {
userId,
userPass,
});
await commit("setSeq", res.data.user_seq);
await commit("setToken", res.data.accessToken);
await dispatch("getStudyLi");
console.log(state.studyData); //i can see the state changes here
} catch {
console.log("error");
}
},
computed: {
data(){
console.log(this.datas) //not working
return this.$store.state.login.studyData
}
},
You don't have any this.datas property in the code shown.
It is also important how do use the computed. It runs the computed method only if there is some call of computed value. You can not expect method to be called if you do not use this.data property in your component.
U can just use mapState instead, if u not gonna process your studyData anymore and save your time writing this.$store.state.login.studyData
computed: {
...mapState([
"studyData",
"studyData2",
]),
}
Related
I'm trying to figure out how to properly update a getter value when some other variable from VueX changes/updates.
Currently I'm using this way in a component to update:
watch: {
dates () {
this.$set(this.linedata[0].chartOptions.xAxis,"categories",this.dates)
}
}
So my getter linedata should be updated with dates value whenever dates changes. dates is state variable from VueX store.
The thing is with this method the value won't be properly updated when I changed route/go to different components. So I think it's better to do this kind of thing using the VueX store.
dates is updated with an API call, so I use an action to update it.
So the question is how can I do such an update from the VueX store?
EDIT:
I tried moving this to VueX:
async loadData({ commit }) {
let response = await Api().get("/cpu");
commit("SET_DATA", {
this.linedata[0].chartOptions.xAxis,"categories": response.data.dates1,
this.linedata[1].chartOptions.xAxis,"categories": response.data.dates2
});
}
SET_DATA(state, payload) {
state = Object.assign(state, payload);
}
But the above does not work, as I cannot set nested object in action this way...
Getters are generally for getting, not setting. They are like computed for Vuex, which return calculated data. They update automatically when reactive contents change. So it's probably best to rethink the design so that only state needs to be updated. Either way, Vuex should be updated only with actions/mutations
Given your example and the info from all your comments, using linedata as state, your action and mutation would look something like this:
actions: {
async loadData({ commit }) {
let response = await Api().get("/cpu");
commit('SET_DATA', response.data.dates);
}
}
mutations: {
SET_DATA(state, dates) {
Vue.set(state.linedata[0].chartOptions.xAxis, 'categories', dates[0]);
Vue.set(state.linedata[1].chartOptions.xAxis, 'categories', dates[1]);
}
}
Which you could call, in the component for example, like:
this.$store.dispatch('loadData');
Using Vue.set is necessary for change detection in this case and requires the following import:
import Vue from 'vue';
Theoretically, there should be a better way to design your backend API so that you can just set state.linedata = payload in the mutation, but this will work with what you have.
Here is a simple example of a Vuex store for an user.
export const state = () => ({
user: {}
})
export const mutations = {
set(state, user) {
state.user = user
},
unset(state) {
state.user = {}
},
patch(state, user) {
state.user = Object.assign({}, state.user, user)
}
}
export const actions = {
async set({ commit }) {
// TODO: Get user...
commit('set', user)
},
unset({ commit }) {
commit('unset')
},
patch({ commit }, user) {
commit('patch', user)
}
}
export const getters = {
get(state) {
return state.user
}
}
If you want to set the user data, you can call await this.$store.dispatch('user/set') in any Vue instance. For patching the data you could call this.$store.dispatch('user/patch', newUserData).
The getter is then reactively updated in any Vue instance where it is mapped. You should use the function mapGetters from Vuex in the computed properties. Here is an example.
...
computed: {
...mapGetters({
user: 'user/get'
})
}
...
The three dots ... before the function call is destructuring assignment, which will map all the properties that will the function return in an object to computed properties. Those will then be reactively updated whenever you call dispatch on the user store.
Take a look at Vuex documentation for a more in depth explanation.
I have a variable in the vuex store called permissions. And i want my component to trigger a rerender when the getPermissions changes. In the vue devtools i clearly see that the state has changed in the store, but the component stil get the old state from getPermissions. In order for me to see changes, I have to do a refresh. Has it something to do with the way i mutate it? or the fact that it is an object?
It looks like this when populated:
permissions: {
KS1KD933KD: true,
KD9L22F732: false
}
I use this method to do mutations on it and a getter to get it:
const getters = {
getPermissions: state => state.permissions
};
const mutations = {
set_recording_permissions(state, data) {
let newList = state.permissions;
newList[data.key] = data.bool;
Vue.set(state, 'permissions', newList);
}
};
And in the component i use mapGetters to get access to it
computed: {
...mapGetters('agentInfo',['getPermissions'])
}
In order to update the permissions value i use this action (it does require a succesfull api request before updating the value) :
const actions = {
async setRecordingPermissions({ commit }, data) {
let body = {
agentId: data.userName,
callId: data.callId,
allowUseOfRecording: data.allowUseOfRecording
};
try {
await AgentInfoAPI.editRecordingPermissions(body).then(() => {
commit('set_recording_permissions', { key: data.callId, bool: data.allowUseOfRecording });
commit('set_agent_info_message', {
type: 'success',
text: `Endret opptaksrettigheter`
});
});
} catch (error) {
console.log(error);
commit('set_agent_info_message', {
type: 'error',
text: `Request to ${error.response.data.path} failed with ${error.response.status} ${error.response.data.message}`
});
}
}
}
Since the getter only returns state variable you should use mapState, if you want to access it directly.
computed: mapState(['permissions'])
However, you can also use mapGetters, but then in your template, have to use getPermissions and not permissions.
Example template:
<ul id="permissions">
<li v-for="permission in getPermissions">
{{ permission }}
</li>
</ul>
If you have done this it is probably an issue with the object reference. You use Vue.set, but you set the same object reference. You have to create a new object or set the key you want to update directly.
new object
let newList = { ...state.permissions };
Vue.set
Vue.set(state.permission, data.key, data.value);
I don't know what the rest of you code looks like, but you will need to use actions to correctly mutate you store.
For example:
const actions = {
setName({ commit }, name) {
commit('setName', name);
},
}
I have a Vuex state that holds a user ID. In my component's mounted(), I try to use that user ID, but it's always null.
How do I get the state from my computed mapGetters into my mounted()?
Here's my computed:
computed: {
...mapGetters('auth', [
'userid'
])
}
And here's my mounted():
mounted () {
HTTP.get('account/' + this.userid + '/')
.then((response) => {
this.account = response.data
})
}
The this.userid is always null.
BTW when I look at the Vue inspector, the auth/userid has the correct value in the getter auth/userid. How do I access auth.userid from mounted()?
userid might not be available at the time component is mounted. You can fix it by watching userid value, and only call HTTP request when userid is changed and available:
computed: {
...mapGetters('auth', [
'userid'
])
},
watch: {
'userid': {
handler (newVal) {
if (newVal) { // check if userid is available
this.getAccountInformation()
}
},
immediate: true // make this watch function is called when component created
}
},
methods: {
getAccountInformation () {
HTTP.get('account/' + this.userid + '/')
.then((response) => {
this.account = response.data
})
}
}
DEBUG
To debug this, first skip the mapGetters, and even getters, and return your state directly.
For example.
computed:{
userId() { return this.$store.state.auth.userid }
}
I don't know how your store or modules are set up, so you might have to change things a bit.
Once that works, add it to your getters and use this.$store.getters.userid, or such.
Finally, when that works, try your original mapGetters and double check your module alias.
POSSIBLE ASYNC ISSUE
Now, on the other hand, if your getter is async, you will also get a null, before the userid promise resolves. You would have to use an asyncComputed, or wait for the result in your mounted.
import { remoteSettings } from 'somewhere';
const store = {
state: {
view: {
foo: true
}
},
mutations: {
toggleFoo(state) {
state.view.foo = !state.view.foo;
}
},
actions: {
async toggleFoo({ state, commit }) {
commit('toggleFoo');
await remoteSettings.save(state);
}
}
};
Say I have a simple store like this. toggleFoo action applies the mutation, then saves the new state by making an async call. However, if remoteSettings.save() call fails, local setting I have in the store and remote settings are out of sync. What I really want to achieve in this action is something like this:
async toggleFoo({ state, commit }) {
const newState = simulateCommit('toggleFoo');
await remoteSettings.save(newState);
commit('toggleFoo');
}
I'd like to get the new state without actually committing it. If remote call succeeds, then I'll actually update the store. If not, it's going to stay as it is.
What's the best way to achieve this (without actually duplicating the logic in the mutation function)? Maybe "undo"? I'm not sure.
One way of doing this would be: (credit to #Bert for correcting mistakes)
Store the old state using const oldState = state; before committing the mutation.
Wrap the async call in a try-catch block.
If the remoteSettings fails it will pass the execution to catch block.
In the catch block commit a mutation to reset the state.
Example:
const store = {
state: {
view: {
foo: true
}
},
mutations: {
toggleFoo(state) {
state.view.foo = !state.view.foo;
},
resetState(state, oldState){
//state = oldState; do not do this
//use store's instance method replaceState method to replace rootState
//see : https://vuex.vuejs.org/en/api.html
this.replaceState(oldState)
}
},
actions: {
async toggleFoo({ state, commit }) {
const oldState = JSON.parse(JSON.stringify(state)); //making a deep copy of the state object
commit('toggleFoo');
try {
await remoteSettings.save(newState);
//commit('toggleFoo'); no need to call this since mutation already commited
} catch(err) {
//remoteSettings failed
commit('resetState', oldState)
}
}
}
};
Borrowing code from #VamsiKrishna (thank you), I suggest an alternative. In my opinion, you want to send the changes to the server, and update the local state on success. Here is a working example.
To prevent duplicating logic, abstract the change into a function.
console.clear()
const remoteSettings = {
save(state){
return new Promise((resolve, reject) => setTimeout(() => reject("Server rejected the update!"), 1000))
}
}
function updateFoo(state){
state.view.foo = !state.view.foo
}
const store = new Vuex.Store({
state: {
view: {
foo: true
}
},
mutations: {
toggleFoo(state) {
updateFoo(state)
},
},
actions: {
async toggleFoo({ state, commit }) {
// Make a copy of the state. This simply uses JSON stringify/parse
// but any technique/library for deep copy will do. Honestly, I don't
// think you would be sending the *entire* state, but rather only
// what you want to change
const oldState = JSON.parse(JSON.stringify(state))
// update the copy
updateFoo(oldState)
try {
// Attempt to save
await remoteSettings.save(oldState);
// Only commit locally if the server OKs the change
commit('toggleFoo');
} catch(err) {
// Otherwise, notify the user the change wasn't allowed
console.log("Notify the user in some way that the update failed", err)
}
}
}
})
new Vue({
el: "#app",
store,
computed:{
foo(){
return this.$store.state.view.foo
}
},
mounted(){
setTimeout(() => this.$store.dispatch("toggleFoo"), 1000)
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vuex/3.0.1/vuex.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.9/vue.js"></script>
<div id="app">
<h4>This value never changes, because the server rejects the change</h4>
{{foo}}
</div>
How can i destroy this watcher? I need it only one time in my child component, when my async data has loaded from the parent component.
export default {
...
watch: {
data: function(){
this.sortBy();
},
},
...
}
gregor ;)
If you construct a watcher dynamically by calling vm.$watch function, it returns a function that may be called at a later point in time to disable (remove) that particular watcher.
Don't put the watcher statically in the component, as in your code, but do something like:
created() {
var unwatch = this.$watch(....)
// now the watcher is watching and you can disable it
// by calling unwatch() somewhere else;
// you can store the unwatch function to a variable in the data
// or whatever suits you best
}
More thorough explanation may be found from here: https://codingexplained.com/coding/front-end/vue-js/adding-removing-watchers-dynamically
Here is an example:
<script>
export default {
data() {
return {
employee: {
teams: []
},
employeeTeamsWatcher: null,
};
},
created() {
this.employeeTeamsWatcher = this.$watch('employee.teams', (newVal, oldVal) => {
this.setActiveTeamTabName();
});
},
methods: {
setActiveTeamTabName() {
if (this.employee.teams.length) {
// once you got your desired condition satisfied then unwatch by calling:
this.employeeTeamsWatcher();
}
},
},
};
</script>
If you are using vue2 using the composition-api plugin or vue3, you can use WatchStopHandle which is returned by watch e.g.:
const x = ref(0);
setInterval(() => {
x.value++;
}, 1000);
const unwatch = watch(
() => x.value,
() => {
console.log(x.value);
x.value++;
// stop watch:
if (x.value > 3) unwatch();
}
);
For this kind of stuff, you can investigate the type declaration of the API, which is very helpful, just hover the mouse on it, and it will show you a hint about what you can do: