Vue - Passing component data to view - vue.js

Hi I'm looking at Vue and building a website with a Facebook login. I have a Facebook login component, which works, although I'm having difficulty making my acquired fbid, fbname, whatever available to my Vues outside the component. Acknowledged this most likely this is a 101 issue, help would be appreciated.
I've tried the global "prototype" variable and didn't manage to get that working. How's this done?
Code below:
main.js
new Vue({
router,
render: h => h(App),
vuetify: new Vuetify()
}).$mount('#app')
App.vue
...
import FacebookComp from './components/FacebookComp.vue'
export default {
name: 'app',
components: {
FacebookComp
},
...
}
Component - FacebookComp.vue
<template>
<div class="facebookcomp">
<facebook-login class="button"
appId="###"
#login="checkLoginState"
#logout="onLogout"
#get-initial-status="checkLoginState">
</facebook-login>
</div>
</template>
<script>
//import facebookLogin from 'facebook-login-vuejs';
//import FB from 'fb';
export default {
name: 'facebookcomp',
data: {
fbuserid: "string"
},
methods: {
checkLoginState() {
FB.getLoginStatus(function(response) {
fbLoginState=response.status;
});
if(fbLoginState === 'connected' && !fbToken){
fbToken = FB.getAuthResponse()['accessToken'];
FB.api('/me', 'get', { access_token: fbToken, fields: 'id,name' }, function(response) {
fbuserid=response.id;
});
}
},
...
}
VIEW - view.vue
...
export default {
name: 'view',
data: function() {
return {
someData: '',
},
mounted() {
alert(this.fbloginId); //my facebook ID here
},
...
}

If you would like to have all these props from FB login available throughout your whole app, I strongly suggest using vuex. If you are not familiar with state management in nowadays SPAs, you basically have global container - state. You can change it only via functions called mutations (synchronous). However, you cannot call them directly from your component. That's what functions called actions (asynchronous) are for. The whole flow is: actions => mutations => state. Once you have saved your desired data in state, you can access it in any of your vue component via functions called getters.
Another option, in case you just need the data visible in your parent only, is to simply emit the data from FacebookComp.vue and listen for event in View.vue. Note that to make this work, FacebookComp.vue has to be a child of View.vue. For more info about implementation of second approach, please look at docs.

Related

Vue3 - after provide/inject object inside component is loosing data

I'm having small issue with provide/inject in my project.
In App.vue, I'm pulling data from DB and pushing it into object. With console log I checked and all data it's there.
<template>
<router-view />
</template>
<script>
export default {
provide() {
return {
user: this.user,
};
},
data() {
return {
user: '',
};
},
methods: {
///pulling data from DB
func() {
fetch("url")
.then((response) => {
if (response.ok) {
return response.json();
}
})
.then((data) => {
const user = [];
for (const id in data) {
user.push({
id: data[id].user_id,
firstName: data[id].user_firstname,
lastName: data[id].user_lastname,
email: data[id].user_email,
phone: data[id].user_phone,
address1: data[id].user_address_1,
address2: data[id].user_address_2,
address3: data[id].user_address_3,
address4: data[id].user_address_4,
group: data[id].user_group,
});
}
this.user = user;
})
.catch((error) => {
console.log(error);
});
},
},
created() {
this.func();
},
};
</script>
Console log of object user App.vue
Object { id: "3", firstName: "test", lastName: "test", … }
Next I'm injecting it into component. Object inside component exists, but empty - all data cease to exist.
<script>
export default {
inject: ["user"],
};
</script>
console log of object user in component
<empty string>
While in App.vue data is still there, in any components object appears to be empty, but it is there. Any idea why?
Thanks for help.
In short, this happens because you are reassigning user rather than changing user.
Let's say you have a Child component that consumes your inject data and renders the users in a list:
<template>
<div> Child </div>
<ul>
<li v-for="user in users" :key="user.id"> {{user.name}} </li>
</ul>
</template>
<script>
import {inject} from "vue";
export default {
name: "Child",
setup() {
const users = inject("users");
return {users};
}
}
</script>
To provide the users from parent component, all you need to ensure is that users itself is a reactive object, and you keep changing it from the parent rather than reassigning it.
I am going to use the composition api to illustrate what I mean. Compared to options api, everything in composition api is just plain javascript hence there is a lot less behind-the-scene magic. At the end I will tell you how options api is related to the composition api.
<template>
<button #click=generateUsers>
Generate Users
</button>
<Child/>
</template>
<script>
import {reactive, provide, toRefs} from "vue";
import Child from "./Child.vue";
export default {
name: "App",
components: {
Child
},
setup() {
const data = reactive({users: ""});
const generateUsers = () => {
// notice here you are REASSIGNING the users
data.users = [
{id: 1, name: "Alice"}, {id: 2, name: "Bob"}
];
console.log(data.users);
}
// this way of provide will NOT work
provide("users", data.users);
// this way works because of toRefs
const {users} = toRefs(data);
provide("users", users);
return {generateUsers};
}
}
</script>
A few things to note:
the data options in the options api is exactly the same as const data = reactive({users: ""}). Vue will run your data() method, from where you have to return a plain object. And then Vue will automatically call reactive to add reactivity to it.
provide, on the other hand, is not doing any magic - neither in options api, nor in the composition api. It just passes whatever it is given to the consuming component without any massaging.
the reason provide("users", data.users) does not work as you would expect is that the way you populate the users is not a change to the same data.users object (which actually is reactive), but a reassign all together.
the reason toRefs works is because toRefs links to the original parent.
With this understanding in mind, to fix your original code, you just need to ensure you change, instead of reassigning, the users. The simplest way is to define user as an array and push into it when you load data. (in contrast to defining it initially as a string and reassigning it later)
P.S. what also works in composition api, and is a lot simpler, is to:
<template>
<button #click=generateUsers>
Generate Users
</button>
<Child/>
</template>
<script>
import {ref, provide} from "vue";
import Child from "./Child.vue";
export default {
name: "App",
components: {
Child
},
setup() {
const users = ref();
const generateUsers = () => {
// notice here you are not reassigning the users
// but CHANGING its value
users.value = [
{id: 1, name: "Alice"}, {id: 2, name: "Bob"}
];
console.log(users.value);
}
provide("users", users);
return {generateUsers};
}
}
</script>

How to use vuex action in function

I'm new to Vue, so it's likely I misunderstand something. I want to call a vuex action inside a local function in App.vue like so:
<template>
<div id="app">
<button #click="runFunction(1)">Test</button>
</div>
</template>
<script>
import { mapActions } from 'vuex'
export default{
data() { return { } },
methods: {
...mapActions(['doAction']),
buttonClicked: (input) => { runFunction(input) }
}
}
function runFunction(input){
doAction({ ID: input });
}
</script>
The action calls a mutation in store.js
import Vue from 'vue'
import Vuex from 'vuex'
Vue.use(Vuex);
export default new Vuex.Store({
state: {
IDs: []
},
mutations: {
doAction: (state, id) => { state.IDs.push(id) }
},
actions: {
doAction: ({ commit }, id) => { commit('doAction', id) }
}
})
I also have a main.js that sets up the vue:
import Vue from 'vue'
import App from './App.vue'
import store from './store'
new Vue({
el: '#app',
store,
render: h => h(App)
})
The error I'm getting is:
ReferenceError: doAction is not defined
at runFunction
How can I call the mapped action inside a function? Version is Vue 2.6.10
There are several problems with defining runFunction as a 'local function':
function runFunction(input){
doAction({ ID: input });
}
Firstly, this is just a normal JavaScript function and the usual scoping rules apply. doAction would need to be defined somewhere that this function can see it. There is no magic link between this function and the component defined in App.vue. The function will be accessible to code in the component, such as in buttonClicked, but not the other way around.
The next problem is that it won't be available within your template. When you write runTemplate(1) in your template that's going to be looking for this.runTemplate(1), trying to resolve it on the current instance. Your function isn't on the current instance. Given your template includes #click="runFunction(1)" I'm a little surprised you aren't seeing a console error warning that the click handler is undefined.
mapActions accesses the store by using the reference held in this.$store. That reference is created when you add the store to your new Vue({store}). The store may appear to be available by magic but it's really just this.$store, where this is the current component.
It isn't really clear why you're trying to write this function outside of the component. The simplest solution is to add it to the methods. It'll then be available to the template and you can access doAction as this.doAction.
To keep it as a separate function you'd need to give it some sort of access to the store. Without knowing why you want it to be separate in the first place it's unclear how best to achieve that.
Of course it is not defined outside your instance .... you have to import the exported store from store.js on your function component :
<script>
import { mapActions } from 'vuex'
import store from 'store.js'
export default{
data() { return { } },
methods: {
...mapActions(['doAction']),
buttonClicked: (input) => { runFunction(input) }
}
}
function runFunction(input){
store.commit({ ID: input });
}
</script>

Call a VueJS method inside a component outside 'export default'

I'm trying to call a function inside 'method' from outside. However, it isn't working.
Github issue reporting the same: https://github.com/vuejs/vue/issues/329
vm.test(); // call a function in method, not working
this.vue.test() // not working
export default {
methods: {
test: function() {
alert('test fuction called');
}
}
}
It is not very clear what the actual goal of the original poster is, however this is how you can call a method on a Vue instance, after creating it:
var viewModel = new Vue({
el: "#app",
data: {
msg: "Hello there"
},
methods: {
test: function() {
alert('test fuction called');
}
}
});
viewModel.test();
Working example: https://jsfiddle.net/Daryn/Lja7pake/3/
If you are exporting a single file component then try this:
example.js
<script>
export default {
methods: {
test: function() {
alert('test fuction called');
}
}
}
</script>
main.js
<script>
import Thing from './example.js';
Thing.test();
</script>
Reference: https://v2.vuejs.org/v2/guide/single-file-components.html
What you are trying to achieve is fundamentally flawed. You can't call a method of a component unless you have a reference to an instance of that particular component. In your code, which particular component is vm referring to?
All you're doing is exporting a Vue component definition from your module; there's no component being instantiated here.
We'll need to see more of your code or a complete explanation of what exactly you're trying to achieve so we can provide an alternative solution. (Why are you trying to call the component's method outside of its definition?)
export default {
...
methods: {
...
},
mounted () {
EventBus.$on(‘EVENT_NAME’, function (payLoad) {
...
});
}
}
This is the way I solved that problem.
For the purpose of this demonstration, we create a new project using Vue/CLI. After installation finished, we make the vm exposed to global. Open src/main.js and edit like so:
src/main.js
import Vue from 'vue';
import App from './App.vue';
var vm = new Vue({
router,
render: h => h(App)
}).$mount('#app');
// Add this line (tambahkan baris berikut):
window.vm = vm;
Leave the generated App.vue like it is. So the first child of vm (vm.$children[0]) is App.vue.
We see that App.vue have a child. That makes HelloWorld.vue component as a grand children of vm (vm.$children[0].$children[0]). Knowing this, we can call the methods from outside 'export default' like this:
src/components/HelloWorld.vue
<template>
<div class="hello">
<button
id="sebuahButton"
class="btn btn-outline-secondary btn-sm"
type="button"
>Click Me, Jose!</button>
<h1>{{ msg }}</h1>
<!-- and some stuff, vue cli default generated code -->
<div>
</template>
<script>
(function() {
// wait for the DOM ready event in plain JavaScript
document.addEventListener("DOMContentLoaded", event => {
document.getElementById("sebuahButton").onclick = function() {
vm.$children[0].$children[0].someAction();
};
});
})();
export default {
name: "HelloWorld",
props: {
msg: String
}
methods: {
someAction () {
// do something (lakukan sesuatu masbro!)
console.log("It's been called from outer space, Luke!");
}
}
}
</script>

Vuex accessing state BEFORE async action is complete

I'm having issues where a computed getter accesses the state before it is updated, thus rendering an old state. I've already tried a few things such as merging mutations with actions and changing state to many different values but the getter is still being called before the dispatch is finished.
Problem
State is accessed before async action (api call) is complete.
Code structure
Component A loads API data.
User clicks 1 of the data.
Component A dispatches clicked data (object) to component B.
Component B loads object received.
Note
The DOM renders fine. This is a CONSOLE ERROR. Vue is always watching for DOM changes and re-renders instantly. The console however picks up everything.
Goal
Prevent component B (which is only called AFTER component) from running its computed getter method before dispatch of component A is complete.
Store.js
import Vue from 'vue'
import Vuex from 'vuex'
import axios from 'axios';
Vue.use(Vuex);
export const store = new Vuex.Store({
state: {
searchResult: {},
selected: null,
},
getters: {
searchResult: state => {
return state.searchResult;
},
selected: state => {
return state.selected;
},
},
mutations:{
search: (state, payload) => {
state.searchResult = payload;
},
selected: (state, payload) => {
state.selected = payload;
},
},
actions: {
search: ({commit}) => {
axios.get('http://api.tvmaze.com/search/shows?q=batman')
.then(response => {
commit('search', response.data);
}, error => {
console.log(error);
});
},
selected: ({commit}, payload) => {
commit('selected', payload);
},
},
});
SearchResult.vue
<template>
<div>
//looped
<router-link to="ShowDetails" #click.native="selected(Object)">
<p>{{Object}}</p>
</router-link>
</div>
</template>
<script>
export default {
methods: {
selected(show){
this.$store.dispatch('selected', show);
},
},
}
</script>
ShowDetails.vue
<template>
<div>
<p>{{Object.name}}</p>
<p>{{Object.genres}}</p>
</div>
</template>
<script>
export default {
computed:{
show(){
return this.$store.getters.selected;
},
},
}
</script>
This image shows that the computed method "show" in file 'ShowDetails' runs before the state is updated (which happens BEFORE the "show" computed method. Then, once it is updated, you can see the 2nd console "TEST" which is now actually populated with an object, a few ms after the first console "TEST".
Question
Vuex is all about state watching and management so how can I prevent this console error?
Thanks in advance.
store.dispatch can handle Promise returned by the triggered action handler and it also returns Promise. See Composing Actions.
You can setup your selected action to return a promise like this:
selected: ({commit}, payload) => {
return new Promise((resolve, reject) => {
commit('selected', payload);
});
}
Then in your SearchResults.vue instead of using a router-link use a button and perform programmatic navigation in the success callback of your selected action's promise like this:
<template>
<div>
//looped
<button #click.native="selected(Object)">
<p>{{Object}}</p>
</button>
</div>
</template>
<script>
export default {
methods: {
selected(show){
this.$store.dispatch('selected', show)
.then(() => {
this.$router.push('ShowDetails');
});
},
},
}
</script>
You can try to use v-if to avoid rendering template if it is no search results
v-if="$store.getters.searchResult"
Initialize your states.
As with all other Vue' data it is always better to initialize it at the start point, even with empty '' or [] but VueJS (not sure if Angular or React act the same, but I suppose similar) will behave much better having ALL OF YOUR VARIABLES initialized.
You can define initial empty value of your states in your store instance.
You will find that helpful not only here, but e.g. with forms validation as most of plugins will work ok with initialized data, but will not work properly with non-initialized data.
Hope it helps.

Best Practice for Reacting to Params Changes with Vue Router

When using Vue Router with routes like /foo/:val you have to add a watcher to react for parameter changes. That results in somewhat annoying duplicate code in all views that have parameters in the URL.
This could look like the following example:
export default {
// [...]
created() {
doSomething.call(this);
},
watch: {
'$route' () {
doSomething.call(this);
}
},
}
function doSomething() {
// e.g. request API, assign view properties, ...
}
Is there any other way to overcome that? Can the handlers for created and $route changes be combined? Can the reuse of the component be disabled so that the watcher would not be necessary at all? I am using Vue 2, but this might be interesting for Vue 1, too.
One possible answer that I just found thanks to a GitHub issue is the following.
It is possible to use the key attribute that is also used for v-for to let Vue track changes in the view. For that to work, you have to add the attribute to the router-view element:
<router-view :key="$route.fullPath"></router-view>
After you add this to the view, you do not need to watch the $route anymore. Instead, Vue.js will create a completely new instance of the component and also call the created callback.
However, this is an all-or-nothing solution. It seems to work well on the small application that I am currently developing. But it might have effects on performance in another application. If you really want to disable the reuse of the view for some routes only, you can have a look at setting the key's value based on the route. But I don't really like that approach.
I used this variant without :key prop on router-view component.
routes.js:
{
path: 'url/:levels(.*)',
name: ROUTES.ANY_LEVEL,
props: true,
component: (): PromiseVue => import('./View.vue'),
},
view.vue
<template>
<MyComponent :config="config" />
</template>
---*****----
<script>
data: () => ({ config: {} }),
methods: {
onConfigurationChanged(route) {
const { params } = route
if (params && params.levels) {
this.config = // some logic
} else {
this.config = null
}
},
},
beforeRouteUpdate(to, from, next) {
this.onConfigurationChanged(to)
next()
},
}
</script>
Inside the component, I use the config as a property. In my case, reactivity is preserved and the component is updated automatically from parameter changes inside the same URL.
Works on Vue 2
vue3 and script setup:
watch(route, () => { fetch()})
in import:
import { watch } from 'vue';
import { useRoute } from 'vue-router';
const route = useRoute()