How can I debug Vue app? - javascript

I have a code that gets json from RESTful API. but It only shows .container and It says that there's nothing in items array. the mysterious thing is it doesn't show any errors about it. so I was trying to debug it showing result from fetch using console.log, so I added like let result = await fetch('video').then(res => res.json()) under the code but It doesn't show anything on browser console. seems like It doesn't run the async getData function but I have no clue..
<template lang="pug">
.container
.columns(v-for="n in lines")
.column.is-3.vid(v-for='item in items')
.panel
p.is-marginless
a(:href='item.videoId')
img(:src='item.thumbnail')
.panel.vidInfo
.columns.hax-text-centered
.column
.panel-item.reddit-ups
span {{ item.score }}
i.fa.fa-reddit-alien.fa-2x
.panel-item.reddit-date
i.fa.fa-calendar.fa-2x
</template>
<script>
export default {
name: 'main',
data: () => ({
items: [],
lines: 0
}),
async getVideo () {
this.items = await fetch('/video').then(res => res.json())
this.lines = Math.ceil(this.items.length/4)
}
}
</script>

There are few issues in your code, and console should warn you about them.
First define data object as ES6 Object Method Shorthand, try to avoid arrow functions:
data() {
return {
items: [],
lines: 0
}
}
Then I guess get video is method, so It should be placed under the methods object:
methods: {
async getVideo () {
this.items = await fetch('/video').then(res => res.json())
this.lines = Math.ceil(this.items.length/4)
}
}
I don't know where you want trigger this method (on click, when instance is created or mounted), but I will use created hook
<script>
export default {
name: 'main',
data() {
return {
items: [],
lines: 0
}
},
methods: {
// I don't think you need async/await here
// fetch would first return something called blob, later you can resolve it and get your data
// but I suggest you to use something like axios or Vue reource
async getVideo () {
await fetch('/video')
.then(res => res.json())
.then(items => this.items = items)
this.lines = Math.ceil(this.items.length/4)
}
},
created() {
this.getVideo()
}
}
</script>

Related

How to get chart data from REST GET to appear during initialisation for this vue component?

I modified an apexcharts Vue component BarChart.vue which is from https://github.com/apexcharts/vue3-apexcharts
I want to retrieve chart data by consuming a REST GET API and insert data into series.
The script portion of this component is as follows;
<script>
/* eslint-disable */
export default {
name: "BarExample",
data: dataInitialisation,
methods: {
updateChart,
},
};
async function makeGetRequest(url) {
const axios = require("axios");
//let res = await axios.get("http://localhost:8080/vue3-apexcharts/data.json");
let res = await axios.get(url);
return res.data;
}
function dataInitialisation() {
let init_data = {
chartOptions: {
chart: {
type: "bar",
stacked: true,
animations: {
enabled: true, //disabling will speed up loading
},
},
},
series: {},
};
var url = "http://localhost:8080/vue3-apexcharts/data.json";
const axios = require("axios");
var data;
makeGetRequest(url).then(
(data) =>
{
console.log(JSON.stringify(data));
init_data.series = data;
}
);
return init_data;
}
I verified that there is nothing wrong with the code for getting the data from REST GET by printing out the data using console.log().
I did some research and it seems I need to use mounted() to get the data to appear on the chart. If this is correct, how do I modify the code to use mounted() to do so?
I am using vue 3.
Couple of things.
Never define functions and logic outside the Vue api inside a Vue component.
What's defined in data, should be defined in data every doc that you will encounter does that the same way. Data Properties and Methods.
Answering your question yes, you need a lifecycle hook for fetching the data from the api when the component mounts, you can read more about lifecycle hooks in this article
// From this line until the end just delete everything.
// Define `methods` and `data` where they belong.
function dataInitialisation() {
let init_data = {
chartOptions: {
Here is a refactored example:
<script>
import axios from 'axios'
export default {
name: 'BarExample',
data() {
return {
url: 'http://localhost:8080/vue3-apexcharts/data.json',
chartOptions: {
chart: {
type: 'bar',
stacked: true,
animations: {
enabled: true
}
}
},
series: {}
}
},
async mounted() {
await this.makeGetRequest()
},
methods: {
updateChart, // Where is this method defined?
async makeGetRequest() {
const { data } = await axios.get(this.url)
this.series = data
}
}
}
</script>
I will answer my own question. The key to the answer comes from the mounted event available in the vue-apexcharts library.
https://apexcharts.com/docs/options/chart/events/
I used this article here as a guide on how to use events in vue3-apexcharts.
https://kim-jangwook.medium.com/how-to-use-events-on-vue3-apexcharts-2d76928f4abc
<template>
<div class="example">
<apexchart
width="500"
height="350"
type="bar"
:options="chartOptions"
:series="series"
#mounted="mounted"
></apexchart>
</div>
</template>
<script>
async function makeGetRequest(url) {
const axios = require("axios");
//let res = await axios.get("http://localhost:8080/vue3-apexcharts/data.json");
let res = await axios.get(url);
return res.data;
}
export default {
name: "BarExample",
data: dataInitialisation,
methods: {
updateChart,
mounted: function(event, chartContext, config) {
console.log("mount event");
var url = "http://localhost:8080/vue3-apexcharts/data.json";
const axios = require("axios");
var data;
makeGetRequest(url).then((data) => {
this.series = data;
});
},
},
};
</script>

Vue async call REST API in Vuex store

My async actions do not run correctly. Im new to Vue and JS and I am not sure what is happening here. I placed some confirm() dialogs within my code, to see which line passed and which not.
Within the ScanView.vue I call my addProduct action. I get the confirm dialog saying "addProduct" and dispatch calles the next callAPI action where I get the "callAPI" confirm dialog but nothing more. Seems like fetch() isnt working at all, because no any other dialog is shown. What am I doing wrong?
ScanView.vue
export default defineComponent({
name: "Home",
methods: {
scanEan() {
// QR Code Scanner Logic
this.$store.dispatch("addProduct", ean);
}
});
main.js
const store = new Vuex.Store({
state: {
products: [{
name: 'Produkt',
ean: '123',
amount: '1',
smallImageUrl: 'smImage',
mediumImageUrl: 'mdImage',
largeImageUrl: 'lgImage',
expiration: []
}]
},
mutations: {
addProduct(state, product) {
state.products.unshift(product);
}
},
actions: {
addProduct(context, ean) {
confirm("addProduct: " + ean);
context.dispatch('callAPI', ean);
},
callAPI(context, ean) {
confirm("callAPI: ");
fetch("https://world.openfoodfacts.org/api/v0/product/" + ean + ".json") //
.then(response => {
confirm("reesponse");
return response.json();
}
) //
.then(data => {
confirm("data: " + data);
context.dispatch('saveProduct', data);
});
},
saveProduct(context, data) {
confirm("saveProduct: ");
const name = data.product.product_name;
const ean = data.code;
const smImage = data.product.image_front_thumb_url;
const mdImage = data.product.image_front_small_url;
const lgImage = data.product.image_front_url;
const expiration = new Array();
const date = new Date(data.product.expiration_date);
expiration.push(date);
const product = new Product(
name,
ean,
smImage,
mdImage,
lgImage,
expiration
)
confirm("Produktdata: " + product);
context.commit('addProduct', product);
}
}
});
app.use(store);
EDIT
I build a simulate button for better testing. QR Scanning does not work in Browser.
Result It does work in Browser. But not on my emulator or android device. Seems like fetch() isnt the right way with ionic-vue. If I catch the error I got TypeError: Failed to fetch...
<template>
<button #click="simulateScan">Simulate Scan</button>
</template>
<script>
export default {
methods: {
simulateScan() {
this.$store.dispatch('addProduct', 737628064502);
}
}
};
</script>
Final Solution
fetch() does not work on android. You have to use something like cordova-http, capacitor-http, ionic-http or else. I used capacitorcommunity-http.
npm install #capacitor-community/http
npx cap sync
import { Http } from '#capacitor-community/http';
[...]
callAPI(context, ean) {
var eanurl = "https://world.openfoodfacts.org/api/v0/product/" + ean + ".json";
Http.get({ url: eanurl}) //
.then(response => {
return response.data;
}
) //
.then(data => {
console.log(data);
context.dispatch('saveProduct', data);
}).catch(error => confirm(error));
},
[...]

How to pass data from Vuejs to vuex Store?

I have a vuejs component and a vuex store.
I would like to send data from vue component to vuejs store and then call a function in vuex that's push data to a db.
I get the data from currentUser (that works), but in vuex store I get the error: Cannot read property 'push' of null.
I run createPost that works but the data does not pushed to vuex store I think because the error above.
#vuejs component
import { mapState, mapGetters, mapMutations, mapActions } from "vuex";
import {
SET_NEWPOST,
ADD_TAGS,
SET_USERDATA,
SET_GENERAL
} from "#/store/posts/mutations";
methods: {
...mapMutations("posts", {
updateInformation: SET_NEWPOST,
setUserData: SET_USERDATA,
addGeneral: SET_GENERAL,
addTags: ADD_TAGS
}),
...mapActions("posts", {
create: "triggerAddProductAction"
}),
async createPost() {
this.updateInformation({
content: this.content,
url: this.newOne
});
this.updateUserData();
this.createOne();
}
}
vuex store
...
const state = {
products: []
}
const mutations = {
[addProduct]: (state, product) => state.products.push(product)
},
const actions: {
createUserProduct: async ({ commit, rootState }, product) => {
const userProductDb = new UserProductsDB(
rootState.authentication.user.id
);
const createdProduct = await userProductDb.create(product);
commit("addProduct", createdProduct);
},
triggerAddProductAction: ({ dispatch, state, commit }) => {
const post = state.newPost;
dispatch("createUserProduct", post);
}
}
Your format I believe is a little off. Try building the store like this. Remember that using arrow functions vs non-arrow functions can also have a side effect in what is being referenced.
Mostly what can be seen, is that I removed the const's, and placed it all in the object literal directly. I also remove the Destructuring of addProduct as it doesn't seem logical here.
const store = new Vuex.Store({
state: {
products: []
},
mutations: {
addProduct: (state, product) => {
state.products.push(product)
console.log('Added Product:', product)
console.log('products', state.products)
}
},
actions: {
async createUserProduct({ commit }, product) {
commit("addProduct", product);
}
}
});
new Vue({
el: "#app",
store,
mounted() {
this.$store.dispatch('createUserProduct', 1)
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/vuex/3.1.0/vuex.min.js"></script>
<div id="app"></div>
I think one of the main problems here is actually that you call mutations directly in your component. Mutations should always be called by actions and not directly. This is because mutations are synchronous and actions can be asynchronous. From Vuex docs:
On to Actions
Asynchronicity combined with state mutation can make your program very hard to reason about. For example, when you call two methods both with async callbacks that mutate the state, how do you know when they are called and which callback was called first? This is exactly why we want to separate the two concepts. In Vuex, mutations are synchronous transactions:
store.commit('increment')
// any state change that the "increment" mutation may cause
// should be done at this moment.
To handle asynchronous operations, let's introduce Actions.
That's why you should have a structure like this:
export const mutations = {
ADD_EVENT(state, event) {
state.events.push(event)
},
SET_EVENTS(state, events) {
state.events = events
},
SET_EVENTS_TOTAL(state, eventsTotal) {
state.eventsTotal = eventsTotal
},
SET_EVENT(state, event) {
state.event = event
}
}
export const actions = {
createEvent({ commit, dispatch }, event) {
return EventService.postEvent(event)
.then(() => {
commit('ADD_EVENT', event)
commit('SET_EVENT', event)
const notification = {
type: 'success',
message: 'Your event has been created!'
}
dispatch('notification/add', notification, { root: true })
})
.catch(error => {
const notification = {
type: 'error',
message: 'There was a problem creating your event: ' + error.message
}
dispatch('notification/add', notification, { root: true })
throw error
})
}
Check also this video out by vuemastery even featured on the official vuex docs: https://www.vuemastery.com/courses/mastering-vuex/intro-to-vuex/

VueJS how to use _.debounce on data changes

I'm building a little vue.js-application where I do some post requests. I use the watch-method to whach for api changes which then updates the component if the post request is successfull. Since the watcher constantly checks the API I want to add the ._debounce method but for some reason it doesn't work.
here is the code:
<script>
import _ from 'lodash'
export default {
data () {
return {
cds: [],
cdCount: ''
}
},
watch: {
cds() {
this.fetchAll()
}
},
methods: {
fetchAll: _.debounce(() => {
this.$http.get('/api/cds')
.then(response => {
this.cds = response.body
this.cdCount = response.body.length
})
})
},
created() {
this.fetchAll();
}
}
</script>
this gives me the error: Cannot read property 'get' of undefined
Can someone maybe tell me what I'm doing wrong?
EDIT
I removed the watch-method and tried to add
updated(): {
this.fetchAll()
}
with the result that the request runs in a loop :-/ When I remove the updated-lifecycle, the component does (of course) not react to api/array changes... I'm pretty clueless
Mind the this: () => { in methods make the this reference window and not the Vue instance.
Declare using a regular function:
methods: {
fetchAll: _.debounce(function () {
this.$http.get('/api/cds/add').then(response => {
this.cds = response.body
this.cdCount = response.body.length
})
})
},
Other problems
You have a cyclic dependency.
The fetchAll method is mutating the cds property (line this.cds = response.body) and the cds() watch is calling this.fetchAll(). As you can see, this leads to an infinite loop.
Solution: Stop the cycle by removing the fetchAll call from the watcher:
watch: {
cds() {
// this.fetchAll() // remove this
}
},

Get Vue to update view/component

I'm stuck at a crossroads with a component I am working on.
I have the following component "RecentUpdates"
Within it I am passing props down to a few other components, as you can see from the top of the file.
My problem is when adding a new post, I can not figure out how to get the correct update object array back and i also can not figure out the correct 'Vue way' to update the data prop that is being passed down to the "PostList" component.
<template>
<div>
<PostFilter v-on:selectedCategory="getSelectedPosts" v-on:showAllPosts="showAllPosts" :user="user" :categories="categories"/>
<PostList v-if="recent_posts[0]" :categories="categories" :posts="recent_posts[0]" :user="user"/>
<Pagination v-on:getPreviousPage="getPreviousPage" v-on:getNextPage="getNextPage"/>
</div>
</template>
<script>
import PostList from './PostList';
import PostFilter from './PostFilter';
import Pagination from './Pagination';
import EventBus from '../event-bus';
export default {
name: 'RecentUpdates',
data: () => ({
errors: [],
recent_posts: [],
}),
props: ['categories', 'user'],
components: {
PostList,
PostFilter,
Pagination
},
created() {
if (this.user.meta.selected_categories[0] == 0) {
this.showAllPosts();
}
// do not call here, not working as expected
// is switching selected category to an incorrect one
// this.updateList();
this.getSelectedCategory();
},
watch: {
recent_posts: function(newValue) {
EventBus.$on('addPost', function(newPost) {
console.log(newPost);
this.$forceUpdate();
//this.recent_posts.push(newPost);
//this.$set(this.recent_posts, newPost, newPost);
// this.$nextTick(function () {
// this.recent_posts.push(newPost);
// });
});
console.log(this.recent_posts[0]);
// this.$nextTick(function () {
// console.log(this.recent_posts[0]) // => 'updated'
// });
// if (this.user.meta.selected_categories[0] == 0) {
// EventBus.$on('addPost', this.showAllPosts);
// } else {
// EventBus.$on('addPost', this.getSelectedCategory);
// }
//this.updateList();
}
},
methods: {
// updateList() {
// if (this.user.meta.selected_categories[0] == 0) {
// EventBus.$on('addPost', this.showAllPosts);
// //EventBus.$emit('newPost');
// } else {
// EventBus.$on('addPost', this.getSelectedCategory);
// //EventBus.$emit('newPost');
// }
// },
getSelectedCategory() {
let categoryId = this.user.meta.selected_categories[0];
this.getSelectedPosts(categoryId);
},
showAllPosts() {
axios.get('/wp-json/wp/v2/posts?_embed=true&status=[publish,resolved,unresolved]',
{headers: {'X-WP-Nonce': portal.nonce}})
.then(response => {
this.recent_posts = [];
//this.recent_posts = response.data;
//console.log(response.data);
this.recent_posts.push(response.data);
console.log(this.recent_posts[0]);
})
.catch(e => {
this.errors.push(e);
});
},
getSelectedPosts(categoryId) {
axios.get('/wp-json/wp/v2/posts?_embed=true&status=[publish,resolved,unresolved]&categories=' + categoryId,
{headers: {'X-WP-Nonce': portal.nonce}})
.then(response => {
this.recent_posts = [];
//console.log(response.data);
this.recent_posts.push(response.data);
console.log(this.recent_posts[0]);
})
.catch(e => {
this.errors.push(e);
});
},
/**
* Pagination methods
*
*/
getPreviousPage(page) {
axios.get('/wp-json/wp/v2/posts?_embed=true&status=[publish,resolved,unresolved]&page=' + page,
{headers: {'X-WP-Nonce': portal.nonce}})
.then(response => {
this.recent_posts = response.data;
})
.catch(e => {
this.errors.push(e);
});
},
getNextPage(page) {
axios.get('/wp-json/wp/v2/posts?_embed=true&status=[publish,resolved,unresolved]&page=' + page,
{headers: {'X-WP-Nonce': portal.nonce}})
.then(response => {
this.recent_posts = response.data;
})
.catch(e => {
this.errors.push(e);
});
}
},
}
</script>
<style>
</style>
So there are a number of issues I see reading through your code.
You have a recent_posts data property, which is an array. When you make your ajax call to get the posts you push the response which is also an array into the recent_posts array. Why? Why not just set recent_posts = response.data? Then you won't have to be passing recent_posts[0] around.
You're setting up your EventBus handler inside a watcher. This is really unusual. Typically you would set up a handler inside created or mounted.
this inside the EventBus handler likely refers to the EventBus and not your Vue. Ideally, you would set the handler to be a method on the component, which is already bound to the Vue. Something like EventBus.$on("addPost", this.addPost).
Once you've done all that, adding a new post should be as simple as this.recent_posts.push(newPost).
Here is what I might recommend.
export default {
name: 'RecentUpdates',
data(){
return {
errors: [],
recent_posts: []
}
},
props: ['categories', 'user'],
components: {
PostList,
PostFilter,
Pagination
},
created() {
if (this.user.meta.selected_categories[0] == 0) {
this.showAllPosts();
}
this.getSelectedCategory();
EventBus.$on("addPost", this.addPost)
},
beforeDestroy(){
EventBus.$off("addPost", this.addPost)
},
methods: {
getPosts(url){
axios.get(url, {headers: {'X-WP-Nonce': portal.nonce}})
.then(response => this.recent_posts = response.data)
.catch(e => this.errors.push(e))
},
showAllPosts() {
const url = '/wp-json/wp/v2/posts?_embed=true&status=[publish,resolved,unresolved]';
this.getPosts(url);
},
getSelectedPosts(categoryId) {
const url = '/wp-json/wp/v2/posts?_embed=true&status=[publish,resolved,unresolved]&categories=' + categoryId;
this.getPosts(url);
},
addPost(newPost){
this.recent_posts.push(newPost)
},
... //other methods
},
}
Try using kebab-case in your event listeners instead of camelCase:
Example: v-on:selectedCategory="getSelectedPosts" should be v-on:selected-category="getSelectedPosts".
Example: v-on:showAllPosts="showAllPosts" should be v-on:show-all-posts="showAllPosts" or even using the shortcut #show-all-posts="showAllPosts".
UPDATE: If you can provide the code of the other components so we can have a clearer vision of your problem, But you only want to track changes that happens on an object or an array in vue.js you need to deep watch them.
your watcher should be :
watch: {
recent_posts: {
deep: true,
handler: function( oldValue, newValue) {
console.log( "recent_posts has changed" );
// A post has been added, updated or even deleted
}
}
}

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