How to properly initialize Vuex state to avoid additional API calls - vue.js

Within a records module, there is an action, getRecords to retrieve all records from the API at /records, which commits the setRecords mutation which sets the state for records. A getter for records also exists.
Within the records vue, the created method calls the getRecords action, and the getter for records is passed to the datatable for display.
Until now everything works, however when navigating on and off the records vue, the API is called each time.
How is the properly handled? Does a best practice exist? I can move the action call to a higher level, but this generates an API that may not be required id the user never visits the records vue.
records module
const getters = {
allRecords: state => state.records
}
const state = {
records: []
}
const actions = {
async getRecords({commit}){
console.log('getting records...');
const response = await axios.get('/api/records')
commit('setRecords', response.data)
},
async addRecord({ commit }, user) {
console.log("user :" + JSON.stringify(user))
const response = await axios.post('/api/records', user)
.catch(err => console.log(err))
commit('addRecord', response.data)
}
}
const mutations = {
setRecords: (state, records) => (state.records = records),
addRecord: (state, user) => ([...state.records, user])
}
export default {
state,
getters,
actions,
mutations
}

I have handled this in various different ways in the past.
If you do not care if the data you are serving might be old, you can simply detect if you already have some items in your array:
const actions = {
async getRecords({ commit, getters }){
if (getters.allRecords.length > 0) {
// Don't bother retrieving them anymore
return;
}
console.log('getting records...');
const response = await axios.get('/api/records')
commit('setRecords', response.data)
},
async addRecord({ commit }, user) {
console.log("user :" + JSON.stringify(user))
const response = await axios.post('/api/records', user)
.catch(err => console.log(err))
commit('addRecord', response.data)
}
}
If you do want to have the updated values in your database, you can consider changing your api to only return changed records after a certain timestamp. For this we need the following:
We need to store the timestamp of our last update. The first time we would retrieve everything, and on subsequent requests we would send the timestamp.
A way to identify which records to update in the local state, and which records to delete or add. Having something like an id on your records might be helpful.
Let's assume that instead of returning a flat array of your records, the api returns a response in the format
{
records: [ ... ],
removedRecords: [ ... ],
timestamp: 123456789
}
You would change your state to
const state = {
records: [],
recordUpdateTimestamp: null
}
Your action would then look something like this:
async getRecords({ commit, state }){
const config = {};
if (state.recordUpdateTimestamp) {
config.params = {
timestamp: state.recordUpdateTimestamp
};
}
console.log('getting records...');
const { data }= await axios.get('/api/records', config)
commit('setRecords', data.records);
commit('removeRecords', data.removedRecords);
commit('setRecordUpdateTimestamp', data.timestamp);
},
I will leave writing the mutations to you.
This would obviously need work in the backend to determine which records to send back, but may have the advantage of cutting down both the amount of returned data and the time processing that data a lot.

FYI you don't need a shallow getter like the one you have.
Meaning that a getter that doesn't compute your state has no value might as well use the state itself.
About the practice, it really depends on how important it is to you that "records" has always the freshest data. If you don't need it to be always fetched, you can have a "initRecords" action to run on your "App.vue" on created hook that you can use to initialize your records. If you need always fresh data, what you have is good enough.

Related

Vuex Getter not pulling data

I have a vuex store that I am pulling data from into a component. When the page loads the first time, everything behaves as expected. Yay.
When I refresh the page data is wiped from the store as expected and pulled again into the store as designed. I have verified this is the case monitoring the state using Vuex dev tools. My getter however doesn't pull the data this time into the component. I have tried so many things, read the documentation, etc and I am stuck.
Currently I am thinking it might be an issue with the argument?...
If I change the argument in the getter, 'this.id' to an actual value (leaving the dispatch alone - no changes there), the getter pulls the data from the store. So it seems the prop, this.id has the correct data as the dispatch statement works just fine. So why then wouldn't the getter work?
this.id source - The header includes a search for the person and passes the id of the person that is selected as the id prop. example data: playerId: 60
Thoughts? Appreciate any help.
This code works on initial page load, but not on page refresh.
props: ["id"],
methods: {
fetchStats() {
this.$store.dispatch("player/fetchPlayer", this.id).then(() => {
// alert(this.id);
this.player = this.$store.getters["player/getPlayerById"](this.id);
this.loading = false;
});
}
},
This code (only changing this.id to '6' on getter) works both on initial load and page refresh.
props: ["id"],
methods: {
fetchStats() {
this.$store.dispatch("player/fetchPlayer", this.id).then(() => {
// alert(this.id);
this.player = this.$store.getters["player/getPlayerById"](6);
this.loading = false;
});
}
},
Here is the getPlayerById getter:
getPlayerById: state => id => {
return state.players.find(plr => plr.playerId === id);
},
Here is the fetchPlayer action:
export const actions = {
fetchPlayer({ state, commit, getters }, id) {
// If the player being searched for is already in players array, no other data to get, exit
if (getters.getIndexByPlayerId(id) != -1) {
return;
}
// If the promise is set another request is already getting the data. return the first requests promise and exit
if (state.promise) {
return state.promise;
}
//We need to fetch data on current player
var promise = EventService.getPlayer(id)
.then(response => {
commit("ADD_PLAYER", response.data);
commit("CLEAR_PROMISE", null);
})
.catch(error => {
console.log("There was an error:", error.response);
commit("CLEAR_PROMISE", null);
});
//While data is being async gathered via Axios we set this so that subsequent requests will exit above before trying to fetch data multiple times
commit("SET_PROMISE", promise);
return promise;
}
};
and mutations:
export const mutations = {
ADD_PLAYER(state, player) {
state.players.push(player[0]);
},
SET_PROMISE(state, data) {
state.promise = data;
},
CLEAR_PROMISE(state, data) {
state.promise = data;
}
};

Nuxt await async + vuex

Im using nuxt and vuex. In vuex im getting data:
actions: {
get_posts(ctx) {
axios.get("http://vengdef.com/wp-json/wp/v2/posts").then(post => {
let posts = post.data;
if (!posts.length) return;
let medias_list = "";
posts.forEach(md => {
medias_list += md.featured_media + ","
});
medias_list = medias_list.slice(0, -1);
let author_list = "";
posts.forEach(md => {
author_list += md.author + ","
});
author_list = author_list.slice(0, -1);
axios.all([
axios.get("http://vengdef.com/wp-json/wp/v2/media?include=" + medias_list),
axios.get("http://vengdef.com/wp-json/wp/v2/users?include=" + author_list),
axios.get("http://vengdef.com/wp-json/wp/v2/categories"),
]).then(axios.spread((medias, authors, categories) => {
ctx.commit("set_postlist", {medias, authors, categories} );
})).catch((err) => {
console.log(err)
});
})
}
},
In vuex state i have dynamic postlist from exaple below.
How i can use it in Nuxt?
In nuxt i know async fetch and asyncData.
async fetch () {
this.$store.dispatch("posts/get_posts");
}
Thats not working.
How i can say to nuxt, wait loading page, before vuex actions loading all data?
As you already mentioned there are:
fetch hook
asyncData
And differences are well described here
The reason why your code is not working might be in your store action.
It should return a promise, try to add return before axios get method ->
get_posts(ctx) {
return axios.get(...
// ...
And then, on your page:
async fetch () {
await this.$store.dispatch("posts/get_posts");
}
Also, in comment above you're saying that you dont want to commit data in store:
...load page only after vuex, i dont need to pass data in vuex
But you do it with this line:
ctx.commit("set_postlist", {medias, authors, categories} );
if you dont want to keep data in store, just replace line above with:
return Promise.resolve({ medias, authors, categories })
and get it on your page:
async fetch () {
this.posts = await this.$store.dispatch("posts/get_posts");
// now you can use posts in template
}
Misread the actual question, hence the update
With Nuxt, you can either use asyncData(), the syntax will change a bit tho and the render will be totally blocked until all the calls are done.
Or use a combo of fetch() and some skeletons to make a smooth transition (aka not blocking the render), or a loader with the $fetchState.pending helper.
More info can be found here: https://nuxtjs.org/docs/2.x/features/data-fetching#the-fetch-hook
Older (irrelevant) answer
If you want to pass a param to your Vuex action, you can call it like this
async fetch () {
await this.$store.dispatch('posts/get_posts', variableHere)
}
In Vuex, access it like
get_posts(ctx, variableHere) {
That you can then use down below.
PS: try to use async/await everywhere.
PS2: also, you can destructure the context directly with something like this
get_posts({ commit }, variableHere) {
...
commit('set_postlist', {medias, authors, categories})
}

Where should I subscribe firebase fetch items

im building an react native with redux and Firebase Realtime Database, and I'm concerned about where to subscribe to fetch my items on a screen.
Im using useEffect to dispatch the subscription to firebase db:
useEffect(() => {
dispatch(userActions.fetchPets());
}, []);
and inside the action
export const fetchPets = () => {
return async dispatch => {
const user = await firebase.auth().currentUser;
firebase
.database()
.ref(`pets/${user.uid}`)
.on("child_added", snapshot => {
const pet = snapshot.val() || null;
dispatch({ type: ADD_PET, payload: pet });
});
};
};
My problem is when my screen re-render this action executes again filling with repeated data.
This is my reducer:
case ADD_PET:
return {
...state,
pets: [...state.pets, action.payload]
};
My question
Should I filter my state with key to delete repeated?
Should I put my subscription in another place? like a middleware or something? there is a pattern for this?
PS: "Sorry by my English"
the pattern you are using is fine.
If inside payload you have an array with new elements you have, your approach works fine. But, im assuming you are getting the same elements, just with any updated property. So, for example, if you have your pets store like this:
pets: [{id: 1, name: 'whatever'}], and your payload is : [{id: 1, name: 'whatever2'}], now you have both concatenated in your store, what is bad, because is the same object, updated.
So, if you will have the full list updated in the request, i would just change your reducer to this:
const initialState = { pets: [] };
case ADD_PET:
return {
...state,
pets: action.payload
};
So everytime you make the api request, you will have the updated list of elements.
Another case is if you get in the request only the updated, and you will have to filter your object based on ids, and then just replace the updated ones. But i dont think it is your case.

Updating getter value Vuex store when state changes

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.

Debounce Vuex Action Call to Database Not Working

I have a few components that can be separate or on the same page. Each of these components uses the same Vuex state. Since they can each be used on other pages and still work, each of them dispatches a call to the same Vuex action which in turns calls a service that uses axios to get the JSON data.
All of this works great!
However, when I do have 2 (or more) of these components on a single page, that axios call gets called 1 time for each of the components. Initially, I went down the path of trying to see if data existed and get created a "last got data at" timestamp so I could just bypass the 2nd call. However, these are happening both on the components created event and are being essentially called at the same time.
So, enter debounce. Seems like the exact reason for this. However, when I implement it, it fails and is passing on to the next line of code and not awaiting. What am I doing wrong?
Agenda Component (one that uses the same state)
async created() {
await this.gatherCalendarData();
},
methods: {
async gatherCalendarData() {
await this.$store.dispatch('time/dateSelected', this.$store.state.time.selectedDate);
},
},
Month Component (another, notice they are the same)
async created() {
await this.gatherCalendarData();
},
methods: {
async gatherCalendarData() {
await this.$store.dispatch('time/dateSelected', this.$store.state.time.selectedDate);
},
},
The Action getting called
async dateSelected(context, data) {
let result = await getCalendarData(isBetween.date, context.rootState.userId);
await context.commit('SET_MONTHLY_DATA', { result: result.Result, basedOn: isBetween.date });
},
This getCalendarData method is in a service file I created to make api calls (below.)
This is the error that I receive (once for each component) that calls this action.
[Vue warn]: Error in created hook (Promise/async): "TypeError: Cannot read property 'Result' of undefined"
Which is referring to the 3rd line above: result: result.Result
API Service
const getCalendarData = debounce(async (givenDate, userId) => {
let response = await getCalendarDataDebounced(givenDate, userId);
return response;
}, 100);
const getCalendarDataDebounced = async (givenDate, userId) => {
let result = await axiosGet('/api/v2/ProjectTime/BuildAndFillCalendarSQL', {
givenDate: givenDate,
userID: userId,
});
return result;
};
Axios Wrapper
const axiosGet = async (fullUrl, params) => {
let result = null;
try {
let response = await axios.get(fullUrl, params ? { params: params } : null);
result = await response.data;
} catch(error) {
console.error('error:', error);
}
return result;
};
If I put console.log messages before, after and inside the getCalendarData call as well as in the getCaledarDataDebounced methods: (assuming just 2 components on the page) the 2 before logs show up and then the 2 after logs appear. Next the error mentioned above for each of the 2 components, then a single 'inside the getCalendarData' is logged and finally the log from within the debounced version where it actually gets the data.
So it seems like the debouncing is working in that it is only run a single time. But it appears that await call let result = await getCalendarData(isBetween.date, context.rootState.userId); is not truly Waiting.
Am I missing something here?
EDITS after Answer
Based on #JakeHamTexas' answer, my action of dateSelected is now (actual full code, nothing removed like above as to not confuse anything):
async dateSelected(context, data) {
console.log('dateSelected action');
let isBetween = isDateWithinCurrentMonth(data, context.state);
if (!isBetween.result) {
// The date selected is in a different month, so grab that months data
return new Promise(resolve => {
getCalendarData(isBetween.date, context.rootState.userId)
.then(result => {
console.log('inside promise');
context.commit('SET_MONTHLY_DATA', { result: result.Result, basedOn: isBetween.date });
context.commit('SET_SELECTED_DATE', isBetween.date);
context.commit('statistics/TIME_ENTRIES_ALTERED', true, { root: true });
resolve();
});
});
} else {
// The date selected is within the given month, so simply select it
context.commit('SET_SELECTED_DATE', data);
}
context.commit('CLEAR_SELECTED_TIME_ENTRY_ID');
},
And my API call of getCalendarData is now:
const getCalendarData = async (givenDate, userId) => {
console.log('getting calendar data');
let result = await axiosGet('/api/v2/ProjectTime/BuildAndFillCalendarSQL', {
givenDate: givenDate,
userID: userId,
});
return result;
};
The error is gone! However, it does not seem to be debouncing - meaning everything gets called 3 times. I would expect the dateSelected action to be called 3 times. But I would like to avoid the getting calendar data being called 3 times. If it helps, this is what the console looks like:
dateSelected action
getting calendar data
dateSelected action
getting calendar data
dateSelected action
getting calendar data
inside promise
inside promise
inside promise
You need to return a promise from your action. Returning a promise of undefined (which is what is currently happening) resolves immediately.
dateSelected(context, data) {
return new Promise(resolve => {
getCalendarData(isBetween.date, context.rootState.userId)
.then(result => {
context.commit('SET_MONTHLY_DATA', { result: result.Result, basedOn: isBetween.date });
resolve();
}
}
},
Additionally, a vuex commit does not return a promise, so it doesn't make sense to await it.