My user state variable is an object having several properties such as first_name. I want to display some of these properties in my component template.
I'm assign my state variable to a computed property which I use in template thus:
<template>
<div>
{{ user.first_name }}
</div>
</template>
<script>
import { mapState } from "vuex";
export default {
computed: {
...mapState({
user: state => state.dashboard.user
})
},
beforeMount () {
this.$store.dispatch("dashboard/getUser");
}
};
</script>
Although it works, I get the following error in console:
Error in render: "TypeError: Cannot read property 'title' of null"
I suppose it's because user is null for a split second as component mounts, till it receives info that Vue correctly displays in template. How to avoid the error though?
[EDIT] here are the relevant part of the store:
state: {
user: null
},
...
actions: {
async getUser({ commit }) {
let user = await axios.get(`user`).catch(console.error);
commit("SET_USER", user);
return user;
}
},
In your mapped getter you could default to an empty object like
state => state.dashboard.user || {}
That way things like user.first_name would be undefined rather than attempting to look for a property on the value null
Ok. I've rewritten the code.
store.js
state: {
user: ''
},
mutations: {
SET_USER: (state, user) => {
state.user = user
}
},
actions: {
getUser: (context, user) => {
axios.get('url/to/server')
.then(res => {
context.commit('SET_USER', res.data)
})
.catch(error => {
console.log(error)
})
}
}
Now in your root component (App.vue for example)
import {mapActions} from 'vuex'
export default{
...
mounted() {
this.getUser()
},
methods: {
...mapActions(['getUser'])
}
}
In the component, you wish to use the user data
<template>
<div>
{{user.first_name}}
</div>
<template/>
import {mapState} from 'vuex'
export default{
computed: {
...mapState(['user'])
}
}
This will work.
Hope it helps.
Related
I am trying to make use of mapState and running into issues with reactive data. I have the following inside my Test.vue component
<template>
<div> {{ name }} </div>
</template>
computed: {
...mapState('user', ['age','name]
}
when my state user.name updates outside of the Test.vue component, the new value is not showing inside Test.vue.
so for example, if I have an update via a mutation in my userStore,
[SET_USER_NAME_MUTATION](state, value) {
state.name = value;
},
commit('SET_USER_NAME_MUTATION', "John")
now in my Vuex store when I check chrome DevTools , user { name: "John" } , which is correct
You should mutate state through vuex actions instead of directly calling the mutation.
Try with something like this, assuming your state contains a user object with name property:
Vue component
<template>
<div>
<span>{{ name }}</span>
<button #click="changeName">Change name</button>
</div>
</template>
<script>
import { mapState } from 'vuex'
export default {
name: 'MyComponent',
computed: {
...mapState({
name: state => state.user.name
})
},
methods: {
changeName () {
this.$store.dispatch('changeName', 'John Smith')
}
}
}
</script>
Vuex store
// state
const state = {
user: {
name: null
}
}
// getters
const getters = {
// ...
}
// actions
const actions = {
changeName ({ commit }, payload) {
commit('setName', payload)
}
}
// mutations
const mutations = {
setName (state, payload) {
state.user.name = payload
}
}
export default {
namespaced: true,
state,
getters,
actions,
mutations
}
Anyway, it will be very helpful to know your state structure to a better approach as per your specific case
I have an action in Vuex actions which commit a mutation that it take a payload from the component, that is a number of the index for returning an object, it works fine on Vuex js file meaning that shows the selected item on the console, as I said it gets index from the payload,
but on the component, it gives me Promise <Pending>, why that's happening? for now, I do not use any API for my Nuxt/Vue app, but I will, and for now, I just want to know why this is happening and what is the best solution for solving this
Here my Vuex codes:
export const state = () => ({
articles: [
{
uid: 0,
img: 'https://raw.githubusercontent.com/muhammederdem/mini-player/master/img/1.jpg',
link: '/articles/1',
},
{
uid: 1,
img: 'https://raw.githubusercontent.com/muhammederdem/mini-player/master/img/2.jpg',
link: '/articles/2',
},
],
})
export const getters = {
getArticles(state) {
return state.articles
},
}
export const mutations = {
getSpeceficArticle(state, payload) {
return state.articles[payload]
},
}
export const actions = {
getSpeceficArticle({ commit }, payload) {
commit('getSpeceficArticle', payload)
},
}
and here my component codes:
<template>
<div class="article">
{{ getSpeceficArticle() }}
<div class="article__banner">
<img src="" alt="" />
</div>
<div class="article__text">
<p></p>
</div>
</div>
</template>
<script>
export default {
name: 'HomeArticlesArticle',
data() {
return {
item: '',
}
},
// computed: {},
methods: {
async getSpeceficArticle() {
return await this.$store.dispatch('articles/getSpeceficArticle', 0)
},
},
}
</script>
actions are used to update the state they are like mutations but the main difference between them is that actions can include some asynchronous tasks, if you want to get a specific article at given index you should use a getter named getArticleByIndex :
export const getters = {
getArticles(state) {
return state.articles
},
getArticleByIndex:: (state) => (index) => {
return state.articles[index]
}
}
then define a computed property called articleByIndex :
<script>
export default {
name: 'HomeArticlesArticle',
data() {
return {
item: '',
}
},
computed: {
articleByIndex(){
return this.$store.getters.articles.getArticleByIndex(0)
}
},
methods: {
},
}
</script>
#Mohammad if you find yourself using a lot of getters/actions etc from Vuex and they're starting to get a little wordy, you can bring in mapGetters from Vuex and rename your calls to something a little more convenient. So your script would become,
<script>
import { mapGetters } from 'vuex'
export default {
name: 'HomeArticlesArticle',
data() {
return {
item: '',
}
},
computed: {
articleByIndex(){
return this.getArticleByIndex(0)
}
},
methods: {
...mapGetters({
getArticleByIndex: 'articles/getArticleByIndex',
})
},
}
</script>
You can add ...mapGetters, ...mapActions to your computed section also.
since there is no web service call in vuex action, try to remove async and await keywords from the component.
Later when you add a webservice call than you can wrap action body in new Promise with resolve and reject and then you can use async and await in component. let me know if this works for you.
I am having an issue using lodash's cloneDeep to clone the user object passed in from the store. When I attempt to render the data in the template {{ user }} shows the data retrieved from the store and {{ userCopy }} shows the empty store. I am not sure why this is happening, I am new to Vue.
store/staff.js
import StaffService from '~/services/StaffService.js'
export const state = () => ({
user: {
offers: '',
legal: ''
}
})
export const mutations = {
SET_USER(state, user) {
state.user = user
},
}
export const actions = {
fetchUser({ commit, getters }, id) {
const user = getters.getUserById(id)
if (user) {
commit('SET_USER', user)
} else {
StaffService.getUser(id)
.then((response) => {
commit('SET_USER', response.data)
})
.catch((error) => {
console.log('There was an error:', error.response)
})
}
},
}
export const getters = {
getUserById: (state) => (id) => {
return state.staff.find((user) => user.id === id)
}
}
pages/settings/_id.vue
<template>
<div>
{{ user }} // will display the whole object
{{ userCopy }} // will only display empty store object
</div>
</template>
<script>
import _ from 'lodash'
data() {
return {
userCopy: _.cloneDeep(this.$store.state.staff.user)
}
},
computed: {
...mapState({ user: (state) => state.staff.user })
},
created() {
this.$store.dispatch('staff/fetchUser', this.$route.params.id)
},
</script>
My guess would be that a Vue instance's data is initialized before state becomes available. While computed props are populated/updated as their data source change.
If the component doesn't need to change the value of user during runtime, I'd suggest turning it into a computed property.
If your component does change the value during runtime (such as when it's v-model'd to an input), there are two approaches you can do.
Method 1: Using mounted hook
This is done by placing user in data property and then assigning a value when the instance is mounted, like so:
mounted () {
this.$data.userCopy = _.cloneDeep(this.$store.state.staff.user)
}
Method 2: Using computed with getter and setter functions.
Normally, you shouldn't change a computed value. But it can be done using a setter function. With this, when Vue detects an attempt to change a computed prop it will execute set() with the old and new values as arguments. This function would change the value at its source, allowing get()'s returned value to reflect this. For example:
computed: {
userCopy: {
get () {
return _.cloneDeep(this.$store.state.staff.user)
},
set (newValue) {
this.$store.commit('updateStaff', newValue) // Replace this line with your equivalent state mutator.
}
}
}
New to using Vue-Multiselect. I am using axios to do a GET request from a JSON placeholder to test.
How do I get the title and post id to show up in my drop down?
Right now, I just get [Object Object] - [title] shown in my select box.
<!-- Vue component -->
<template>
<div>
<multiselect v-model='value' :options='posts' :custom-label='postWithTitle' placeholder='Select one' label='title' track-by='id'></multiselect>
{{ value }}
</div>
</template>
<script>
import Multiselect from "vue-multiselect";
import axios from "axios";
export default {
// OR register locally
components: { Multiselect },
data() {
return {
value: null,
posts: []
};
},
created() {
this.getPosts();
},
methods: {
getPosts() {
axios
.get("https://jsonplaceholder.typicode.com/posts")
.then(response => {
// eslint-disable-next-line
console.log(response);
this.posts = response.data;
})
.catch(error => {
// eslint-disable-next-line
console.log(error);
});
},
postWithTitle(id, title) {
return `${id} - [${title}]`;
}
}
};
</script>
fix:
postWithTitle(option) {
return `${option.id} - [${option.title}]`;
}
explaination:
i saw that when i simply console.logged inside the postWithTitle function:
the custom custom-label attribute was accepting a callback that only accepts one argument. that argument was the entire option object- a single entry of your posts array.
i have one async action vuex, im using map getters and component created function to fetch and fill data, if im using this store data inline object in template view console show error undefined, if i try acces variable only without inline object im getting undefined error for inline object, i think this error about async function not blocking main process component fully loaded and after async function filled variable
actions, state
// state
export const state = {
app: null
}
// getters
export const getters = {
app: state => state.app,
}
// mutations
export const mutations = {
[types.FETCH_APP_SUCCESS] (state, { app }) {
state.app = app
},
[types.FETCH_APP_FAILURE] (state) {
state.app = null
},
[types.UPDATE_APP] (state, { app }) {
state.app = app
}
}
async fetchApp ({ commit }) {
try {
const { data } = await axios.get('/api/app/1')
commit(types.FETCH_APP_SUCCESS, { app: data })
} catch (e) {
commit(types.FETCH_APP_FAILURE)
}
}
component
<template>
<div>
{{app.name}}
</div>
</template>
<script>
import { mapGetters } from 'vuex'
export default {
middleware: 'auth',
created () {
// i try here async and await
this.$store.dispatch('app/fetchApp')
},
computed: mapGetters({
app: 'app/app'
}),
metaInfo () {
return { title: this.$t('home') }
}
}
</script>
state is filled
variable can see in html
but console this error
app/app is initially null, and your template does not have a null check on app.name, which results in the error you saw. You can either conditionally render app.name in the template:
<template>
<div>
<template v-if="app">
{{app.name}}
</template>
</div>
</template>
Or use the empty string as app/app's initial state instead of null in your store.