I'm saving an array into local storage
and adding/removing from the array like.
I want the count of the array to update in the component as and when new items get added to the array in localstorage
I am using a computed property:
numOfCodes: {
// getter
get: function() {
let storageItems = localStorage.getItem("items");
if (storageItems) {
var items = JSON.parse(storageItems);
return items.length;
}
return 0;
}
}
The count is not changing as expected. it remains the same.
I have tried using vuex, but still have the issue. the goal is having the value react to the localstorage change
I think a solution to this would be to use vuex, I've mocked up an example below:
On your component:
computed: {
...mapGetters({
itemsCount: 'mockLocalStorage/itemsCount'
})
},
created() {
this.setItems(...);
},
methods: {
...mapActions({
setItems: 'mockLocalStorage/setItems'
})
}
In vuex:
state = {
items: []
};
getters = {
itemsCount: state => state.items.length
};
actions: {
setItems({ commit }, items) {
localStorage.setItem('items', items);
commit('setItems', items);
}
};
this.itemsCount would then be reactive in your component, and you could create a few more actions to add and remove individual items.
The localStorage does not share the reactivity system of Vue. This whole process is handled by Vue itself. See also here. I think you should be able to manually trigger a re-render by forcing Vue to update all of its components using forceUpdate. However, keep in mind that you would have to trigger the re-render whenever you update the localStorage or whenever you expect it to be updated.
Use a watcher.
props: ['storageItems', 'itemsLength'],
watch: {
storageItems: function(newVal, oldVal) {
this.storageItems = newVal
this.itemsLength = newVal.length
}
}
Related
here is my setup. The state "categories" in the state is fetched async from a json endpoint.
In the component I want to work with this data, but if I reload the page the categories are always empty.
methods: {
onSubmit() {
console.log(this.filter);
},
formCats(items) {
console.log(items);
// const arr = flatten(data);
// console.log(arr);
}
},
created() {
const data = this.categories;
this.formCats(data);
},
computed: {
...mapState(['categories'])
}
I also tried async created() with await this.categories. Also not working as expected! Would be great if someone could help me with this. Thanks!
This is happening because the async fetch doesn't finish until after the component is already loaded. There are multiple ways to handle this, here's one. Remove created and turn formCats method into a computed.
computed: {
...mapState(['categories']),
formCats() {
let formCats = [];
if (this.categories && this.categories.length) {
formCats = flatten(this.categories);
}
return formCats;
}
}
formCats will be an empty array at first, and then it will immediately become your formatted categories when this.categories is finished fetching.
I'm stuck in this situation where I have a getters from Vuex Store, and whenever that getter change (new value update), the local state data(the 'list') should be reassign .
This is my component, which has 'list' in data
And here is my test Successfully change the getSkills to the getSkillsMock, but there is no response from list, list is still an []
You need to set deep to true when watching an array or object so that
Vue knows that it should watch the nested data for changes.
watch: {
getSkills: {
handler () {
this.list = this.getSkills.map(items => {
return { value: items.id, label: items.name }
})
},
deep: true
}
}
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} ${error.response.data.message}`
});
}
}
}
Since the getter only returns state variable you should use mapState, if you want to access it directly.
computed: mapState(['permissions'])
However, you can also use mapGetters, but then in your template, have to use getPermissions and not permissions.
Example template:
<ul id="permissions">
<li v-for="permission in getPermissions">
{{ permission }}
</li>
</ul>
If you have done this it is probably an issue with the object reference. You use Vue.set, but you set the same object reference. You have to create a new object or set the key you want to update directly.
new object
let newList = { ...state.permissions };
Vue.set
Vue.set(state.permission, data.key, data.value);
I don't know what the rest of you code looks like, but you will need to use actions to correctly mutate you store.
For example:
const actions = {
setName({ commit }, name) {
commit('setName', name);
},
}
I am calling inside the computed an action from the store to run it and after I am returning a getter, this will create a loop.
The HTML
{{loadedProjects}}
The computed
computed: {
loadedProjects() {
this.$store.dispatch("getProjects");
return this.$store.getters.loadedProjects;
}
}
The store
import Vuex from "vuex";
import axios from "axios";
const createStore = () => {
return new Vuex.Store({
state: {
loadedProjects: []
},
mutations: {
setProjects(state, projects) {
state.loadedProjects = projects
}
},
actions: {
getProjects(vuexContext) {
console.log("hello1")
return axios.get("THE API URL")
.then(res => {
console.log("hello2")
vuexContext.commit("setProjects", res.data);
})
.catch(e => console.log(e));
}
},
getters: {
loadedProjects(state) {
return state.loadedProjects;
}
}
});
};
export default createStore;
I expect to call my action to populate my state and after to return my state to render my data.
What is the point of using the store action that makes an API call inside the computed property ... maybe you want to trigger loadedProjects change ? ....computed property is not asynchronous so either way the return line will be executed before the you get the response... you might try vue-async-computed plugin OR just use the call on the created hook like you have done which is the better way and you don't have to use a computed property you can just {{ $store.getters.loadedProjects }} on your template
Computed properties should not have side effects (e.g. calling a store action, changing data, and so on). Otherwise it can happen that the triggered side effect could lead to a re-rendering of the component and possible re-fetching of the computed property. Thus, an infinite loop
I changed the code like that:
created: function () {
this.$store.dispatch("getProjects")
},
computed: {
loadedProjects() {
return this.$store.getters.loadedProjects
}
}
It is working now but I would like to know but I have that problem working inside the computed and also I wonder if it's the best solution. Any help????
I'm having trouble understanding how to interact with my local state from my vuex state. I have an array with multiple items inside of it that is stored in vuex state. I'm trying to get that data from my vuex state into my components local state. I have no problems fetching the data with a getter and computed property but I cannot get the same data from the computed property into local state to manipulate it. My end goal is to build pagination on this component.
I can get the data using a getters and computed properties. I feel like I should be using a lifecycle hook somewhere.
Retrieving Data
App.vue:
I'm attempting to pull the data before any components load. This seems to have no effect versus having a created lifecycle hook on the component itself.
export default {
name: "App",
components: {},
data() {
return {
//
};
},
mounted() {
this.$store.dispatch("retrieveSnippets");
}
};
State:
This is a module store/modules/snippets.js
const state = {
snippets: []
}
const mutations = {
SET_SNIPPETS(state, payload) {
state.snippets = payload;
},
}
const actions = {
retrieveSnippets(context) {
const userId = firebase.auth().currentUser.uid;
db.collection("projects")
.where("person", "==", userId)
.orderBy("title", "desc")
.onSnapshot(snap => {
let tempSnippets = [];
snap.forEach(doc => {
tempSnippets.push({
id: doc.id,
title: doc.data().title,
description: doc.data().description,
code: doc.data().code,
person: doc.data().person
});
});
context.commit("SET_SNIPPETS", tempSnippets);
});
}
}
const getters = {
getCurrentSnippet(state) {
return state.snippet;
},
Inside Component
data() {
return {
visibleSnippets: [],
}
}
computed: {
stateSnippets() {
return this.$store.getters.allSnippets;
}
}
HTML:
you can see that i'm looping through the array that is returned by stateSnippets in my html because the computed property is bound. If i remove this and try to loop through my local state, the computed property doesn't work anymore.
<v-flex xs4 md4 lg4>
<v-card v-for="snippet in stateSnippets" :key="snippet.id">
<v-card-title v-on:click="snippetDetail(snippet)">{{ snippet.title }}</v-card-title>
</v-card>
</v-flex>
My goal would be to get the array that is returned from stateSnippets into the local data property of visibleSnippets. This would allow me to build pagination and manipulate this potentially very long array into something shorter.
You can get the state into your template in many ways, and all will be reactive.
Directly In Template
<div>{{$store.state.myValue}}</div>
<div v-html='$store.state.myValue'></div>
Using computed
<div>{{myValue}}</div>
computed: {
myValue() { return this.$store.state.myValue }
}
Using the Vuex mapState helper
<div>{{myValue}}</div>
computed: {
...mapState(['myValue'])
}
You can also use getters instead of accessing the state directly.
The de-facto approach is to use mapGetters and mapState, and then access the Vuex data using the local component.
Using Composition API
<div>{{myValue}}</div>
setup() {
// You can also get state directly instead of relying on instance.
const currentInstance = getCurrentInstance()
const myValue = computed(()=>{
// Access state directly or use getter
return currentInstance.proxy.$store.state.myValue
})
// If not using Vue3 <script setup>
return {
myValue
}
}
I guess you are getting how Flux/Vuex works completely wrong. Flux and its implementation in Vuex is one way flow. So your component gets data from store via mapState or mapGetters. This is one way so then you dispatch actions form within the component that in the end commit. Commits are the only way of modifying the store state. After store state has changed, your component will immediately react to its changes with latest data in the state.
Note: if you only want the first 5 elements you just need to slice the data from the store. You can do it in 2 different ways:
1 - Create a getter.
getters: {
firstFiveSnipets: state => {
return state.snipets.slice(0, 5);
}
}
2 - Create a computed property from the mapState.
computed: {
...mapState(['allSnipets']),
firstFiveSnipets() {
return this.allSnipets.slice(0, 5);
}
}