I'm building an app that a page has some vms, in others not. When we change from one page to another show the following warning:
[Vue warn]: Cannot find element: #element-id
How do I instantiate VMs only if there is the element on the page and avoid the error?
NOTE: I'm using Rails asset pipeline, so, all the javascript is concatenated into a single file.
There are no issues just leaving it as is. This is just a warning that only runs when debug mode is on, so you should have it turned off in production anyway.
If you want to get rid of it, just check if the element exists before launching Vue -
if(document.getElementById("element-id")){
new Vue({...})
}
Ref: How to check if element exists in the visible DOM?
This is a bit of an old question. I found this Vue example being useful
https://v2.vuejs.org/v2/api/#Vue-extend
So you can create a Vue class and initiate it only if the dom element is present in the DOM.
// create constructor
var Profile = Vue.extend({
template: '<p>{{firstName}} {{lastName}} aka {{alias}}</p>',
data: function () {
return {
firstName: 'Walter',
lastName: 'White',
alias: 'Heisenberg'
}
}
})
// create an instance of Profile and mount it on an element
if(document.getElementById("element-id")){
new Profile().$mount('#element-id')
}
Related
Let's say I had this:
var app = new Vue({
el: '#app',
data: {
message: Math.random()
}
})
And let's say that I wanted to see what value data.message had been assigned in the JS console. How would I do this?
Superficially it seems like doing console.log(app.data.message) would do the trick but when I try to do that I get a Uncaught TypeError: Cannot read properties of undefined (reading 'message') error. In fact, it turns out that app.data is undefined.
So how can I do this?
Here's a JS fiddle with this code:
https://jsfiddle.net/dfzun3by/4/
That code is based off of https://v2.vuejs.org/v2/guide/?redirect=true#Declarative-Rendering
As a corollary to this question... in some production code that I'm now responsible for we don't have that - we have something more akin to this in a *.vue file:
export default {
data() {
return {
message: Math.random()
}
}
}
I tried to do console.log(app) in the JS console of the page that that corresponds to and got a Uncaught ReferenceError: app is not defined error so how could I do the same thing in the production code?
You can access the root instance from JS console with:
document.getElementById('app').__vue__.message
or
app.$options.data().message
For inspecting vue SFC, it is better to use Vue Devtools.
Sounds like the Vue.js Devtools extension might be beneficial for you, it'll allow you to see the values of all variables that are available to the Vue template (so everything in data).
https://devtools.vuejs.org/guide/installation.html
You can reference that value doing console.log(this.message). If you want to log the value every time it changes, you can create a watcher for the message and include "console.log(this.message)" in there.
watch: {
message() {
console.log(this.message)
}
}
in my complex Vue project I am getting this console warning:
[Vue warn]: Avoid app logic that relies on enumerating keys on a component instance. The keys will be empty in production mode to avoid performance overhead.
Unfortunately I can not find the reason for this warning just by the above message.
How can I track down the reason for this warning?
Check if your watching an entire route object anywhere in your code. Doing so throws that error (in my case).
Refer this vue documentation on watching routes
Accessing router and current route inside setup
The route object is a reactive object, so any of its properties can be watched and you should avoid watching the whole route object. In most scenarios, you should directly watch the param you are expecting to change.
Was able to fix this with the suggestion done by Glass Cannon.(https://stackoverflow.com/a/70205284/11787139)
To clarify and maybe help someone else: I was trying to send an Axios request to the server of which the data I sent through was composed of a direct component reference emitted by the component function.
Component
saveItem(){
this.saved = true;
setTimeout( this.resetState, 2500);
this.$emit('saveitem', this)
},
Parent
saveitem(e){
const data = {item : e}
axios.post(target, data, {headers . . .).then((response) => {}
})
The error disappeared when I instead fetched the index of the list item by doing so:
saveitem(e){
let item;
this.items.forEach( function(item, index, array) {
if(item.id == e.id) pointer = item
})
data.item = pointer
axios.post(target, data, {headers . . .).then((response) => {}
})
}
So I was also having this issue, but not for the reasons the accepted answer provided. It was occurring due to my Vuex store. After a lot of digging I discovered the cause was the presence of the "CreateLogger" plugin.
So if you're having this issue and it's not due to you watching an entire route, check if you're using the CreateLogger plugin in Vuex. That might be the culprit.
This happens for me when I pass this to a data object
data() {
return {
updateController: new UpdateController({
reportTo: this
})
}
}
This used to work fine with Vue 2 but causes this error in Vue 3.
Making this modification solved the problem for me.
data() {
return {
updateController: new UpdateController({
reportTo: () => this
})
}
}
I know this might be anti-pattern but I needed to inject partial reactivity to a non-reactive part of a JS library and this was the most not complicated way of achieving this that I can think of.
This happens to me when destructuring a ref without .value.
This was happening to me only in Firefox, and when I removed the Vue Dev Tools extension it stopped. After re-installing Vue dev tools it hasn't come back. Make sure you have the latest version of the Vue Dev Tools for your browser.
I’m integrating Vue with a CMS called AEM thats works basically as component base system like Vue works too. But instead of having a webpack and imports of .vue files, every component on this CMS is a new Vue instance (new Vue({…})). So on my page I have a lot of Veu instances that communicate with each other using the same store (vuex).
This is actually working fine, but I have a scenario when I need a CMS component inside another. Since both this components are a unique vue instance and the “el” property from the parent includes the “el” from the child, the child component doesn’t work.
I know that this is not the expected use of this lib, but is there any way that I can tell or share the same “context” on both vue instances or even another approach for this scenario.
Thx,
Alexandre.
There should be only one instance of Vue.
I suggest you to create single empty Vue instance inside the body tag
All your existent Vue instances transform into components
Register all components in the root Vue instance
With this approach it will be fine to nest one component into another
You should use only one Vue instance as #shrpne mentioned.
If you keep instantiating Vue instances for every component, you'll run into issues while debugging or with component communication and overall this becomes very missy and you miss out on parent-child communication and inheritance provided by Vue.
I don't know about your Vue architecture, but I am currently working on a manual for working with Vue in AEM.
The basic premise is to use Vue's inline-template and vanilla-js, No typescript, nodeJS build, jsx or anything else at build time, just vanilla-js so that when your page is loaded and even before your js bundle is present, the DOM is already there, you just need to mount components by instantiating one Vue instance that will mount all components. This is also great for SEO (unless you plan to server-side render Vue components in java... which is possible theoretically, but good luck!)
Here is a sample AEM/Vue component:
<simple-counter inline-template>
<button v-bind:style="style" v-on:click="add">${properties.clicksText || 'clicks: '} {{ counter }}</button>
</simple-counter>
the JS:
notice how it does not have a template in the JS, because it's inlined above
Vue.component('simple-counter', {
data: function() {
return {
counter: 0,
style: {
color: 'red',
width: '200px'
}
}
},
methods: {
add: function() {
this.counter = this.counter + 1;
this.style.color = this.style.color == 'red' ? 'green' : 'red';
}
}
})
You can build more AEM components in this fashion, then at the end of your clientlib when all your Vue components have been registered, you can run:
new Vue({ el: '#app'})
This, off course, assumes that your page body or some other parent element has the id: app.
The second part of this, how do you enable re-mount of components after authoring dialog is submitted, you could just refresh the page.
I have a question about how we can re-mount components without refreshing the page here
The basic idea is to add an afteredit event to the component and run a new Vue instance only on the newly mutated component... still working on that
Solution:
Replace all new Vue(...) stuff into Vue.component(...) Vue.extend(...) etc for better interface management.
Only use ONE Vue instance witch is new Vue({...options})
Slice your vuex store into modules.
Google teacher knows everything.
So I'm building an application using Laravel Spark, and therefore taking the opportunity to learn some Vue.js while I'm at it.
It's taken longer for me to get my head around it than I would have liked but I have nearly got Vue-multiselect working for a group of options, the selected options of which are retrieved via a get request and then updated.
The way in which I've got this far may well be far from the best, so bear with me, but it only seems to load the selected options ~60% of the time. To be clear - there are never any warnings/errors logged in the console, and if I check the network tab the requests to get the Tutor's instruments are always successfully returning the same result...
I've declared a global array ready:
var vm = new Vue({
data: {
tutorinstruments: []
}
});
My main component then makes the request and updates the variable:
getTutor() {
this.$http.get('/get/tutor')
.then(response => {
this.tutor = response.data;
this.updateTutor();
});
},
updateTutor() {
this.updateTutorProfileForm.profile = this.tutor.profile;
vm.tutorinstruments = this.tutor.instruments;
},
My custom multiselect from Vue-multiselect then fetches all available instruments and updates the available instruments, and those that are selected:
getInstruments() {
this.$http.get('/get/instruments')
.then(response => {
this.instruments = response.data;
this.updateInstruments();
});
},
updateInstruments() {
this.options = this.instruments;
this.selected = vm.tutorinstruments;
},
The available options are always there.
Here's a YouTube link to how it looks if you refresh the page over and over
I'm open to any suggestions and welcome some help please!
Your global array var vm = new Vue({...}) is a separate Vue instance, which lives outside your main Vue instance that handles the user interface.
This is the reason you are using both this and vm in your components. In your methods, this points to the Vue instance that handles the user interface, while vm points to your global array that you initialized outside the Vue instance.
Please check this guide page once more: https://v2.vuejs.org/v2/guide/instance.html
If you look at the lifecycle diagram that initializes all the Vue features, you will notice that it mentions Vue instance in a lot of places. These features (reactivity, data binding, etc.) are designed to operate within a Vue instance, and not across multiple instances. It may work once in a while when the timing is right, but not guaranteed to work.
To resolve this issue, you can redesign your app to have a single Vue instance to handle the user interface and also data.
Ideally I would expect your tutorinstruments to be loaded in a code that initializes your app (using mounted hook in the root component), and get stored in a Vuex state. Once you have the data in your Vuex state, it can be accessed by all the components.
Vuex ref: https://vuex.vuejs.org/en/intro.html
Hope it helps! I understand I haven't given you a direct solution to your question. Maybe we can wait for a more direct answer if you are not able to restructure your app into a single Vue instance.
What Mani wrote is 100% correct, the reason I'm going to chime in is because I just got done building a very large scale project with PHP and Vue and I feel like I'm in a good position to give you some advice / things I learned in the process of building out a PHP (server side) website but adding in Vue (client side) to the mix for the front end templating.
This may be a bit larger than the scope of your multiselect question, but I'll give you a solid start on that as well.
First you need to decide which one of them is going to be doing the routing (when users come to a page who is handling the traffic) in your web app because that will determine the way you want to go about using Vue. Let's say for the sake of discussion you decide to authenticate (if you have logins) with PHP but your going to handle the routing with Vue on the front end. In this instance your going to want to for sure have one main Vue instance and more or less set up something similar to this example from Vue Router pretending that the HTML file is your PHP index.php in the web root, this should end up being the only .php file you need as far as templating goes and I had it handle all of the header meta and footer copyright stuff, in the body you basically just want one div with the ID app.
Then you just use the vue router and the routes to load in your vue components (one for each page or category of page works easily) for all your pages. Bonus points if you look up and figure using a dynamic component in your main app.vue to lazy load in the page component based on the route so your bundle stays small.
*hint you also need a polyfill with babel to do this
template
<Component :is="dynamicComponent"/>
script
components: {
Account: () => import('./Account/Account.vue'),
FourOhFour: () => import('../FourOhFour.vue')
},
computed: {
dynamicComponent() {
return this.$route.name;
}
},
Now that we are here we can deal with your multiselect issue (this also basically will help you to understand an easy way to load any component for Vue you find online into your site). In one of your page components you load when someone visits a route lets say /tutor (also I went and passed my authentication information from PHP into my routes by localizing it then using props, meta fields, and router guards, its all in that documention so I'll leave that to you if you want to explore) on tutor.vue we will call that your page component is where you want to call in multiselect. Also at this point we are still connected to our main Vue instance so if you want to reference it or your router from tutor.vue you can just use the Vue API for almost anything subbing out Vue or vm for this. But the neat thing is in your main JS file / modules you add to it outside Vue you can still use the API to reference your main Vue instance with Vue after you have loaded the main instance and do whatever you want just like you were inside a component more or less.
This is the way I would handle adding in external components from this point, wrapping them in another component you control and making them a child of your page component. Here is a very simple example with multiselect pretend the parent is tutor.vue.
Also I have a global event bus running, thought you might like the idea
https://alligator.io/vuejs/global-event-bus/
tutor.vue
<template>
<div
id="user-profile"
class="account-content container m-top m-bottom"
>
<select-input
:saved-value="musicPreviouslySelected"
:options="musicTypeOptions"
:placeholder="'Choose an your music thing...'"
#selected="musicThingChanged($event)"
/>
</div>
</template>
<script>
import SelectInput from './SelectInput';
import EventBus from './lib/eventBus';
export default {
components: {
SelectInput
},
data() {
return {
profileLoading: true,
isFullPage: false,
isModalActive: false,
slackId: null,
isActive: false,
isAdmin: false,
rep: {
id: null,
status: '',
started: '',
email: '',
first_name: '',
},
musicTypeOptions: []
};
},
created() {
if (org.admin) {
this.isAdmin = true;
}
this.rep.id = parseInt(this.$route.params.id);
this.fetchData();
},
mounted() {
EventBus.$on('profile-changed', () => {
// Do something because something happened somewhere else client side.
});
},
methods: {
fetchData() {
// use axios or whatever to fetch some data from the server and PHP to
// load into the page component so say we are getting the musicTypeOptions
// which will be in our selectbox.
},
musicThingChanged(event) {
// We have our new selection "event" from multiselect so do something
}
}
};
</script>
this is our child Multiselect wrapper SelectInput.vue
<template>
<multiselect
v-model="value"
:options="options"
:placeholder="placeholder"
label="label"
track-by="value"
#input="inputChanged" />
</template>
<script>
import Multiselect from 'vue-multiselect';
export default {
components: { Multiselect },
props: {
options: {
type: [Array],
default() {
return [];
}
},
savedValue: {
type: [Array],
default() {
return [];
}
},
placeholder: {
type: [String],
default: 'Select Option...'
}
},
data() {
return {
value: null
};
},
mounted() {
this.value = this.savedValue;
},
methods: {
inputChanged(selected) {
this.$emit('selected', selected.value);
}
}
};
</script>
<style scoped>
#import '../../../../../node_modules/vue-multiselect/dist/vue-multiselect.min.css';
</style>
Now you can insure you are manging the lifecycle of your page and what data you have when, you can wait until you get musicTypeOptions before it will be passed to SelectInput component which will in turn set up Multiselect or any other component and then handle passing the data back via this.$emit('hihiwhatever') which gets picked up by #hihiwhatever on the component in the template which calls back to a function and now you are on your way to do whatever with the new selection and pass different data to SelectInput and MultiSelect will stay in sync always.
Now for my last advice, from experience. Resist the temptation because you read about it 650 times a day and it seems like the right thing to do and use Vuex in a setup like this. You have PHP and a database already, use it just like Vuex would be used if you were making is in Node.js, which you are not you have a perfectly awesome PHP server side storage, trying to manage data in Vuex on the front end, while also having data managed by PHP and database server side is going to end in disaster as soon as you start having multiple users logged in messing with the Vuex data, which came from PHP server side you will not be able to keep a single point of truth. If you don't have a server side DB yes Vuex it up, but save yourself a headache and wait to try it until you are using Node.js 100%.
If you want to manage some data client side longer than the lifecycle of a page view use something like https://github.com/gruns/ImmortalDB it has served me very well.
Sorry this turned into a blog post haha, but I hope it helps someone save themselves a few weeks.
I am just playing around with vuejs router and try to load a component.
I used the sample code and changed foo
// Define some components
var Foo = Vue.extend({
template: require('./components/test.vue')
});
var Bar = Vue.extend({
template: '<p>This is bar!</p>'
});
// The router needs a root component to render.
// For demo purposes, we will just use an empty one
// because we are using the HTML as the app template.
var App = Vue.extend({})
// Create a router instance.
// You can pass in additional options here, but let's
// keep it simple for now.
var router = new VueRouter()
// Define some routes.
// Each route should map to a component. The "component" can
// either be an actual component constructor created via
// Vue.extend(), or just a component options object.
// We'll talk about nested routes later.
router.map({
'/foo': {
component: Foo
},
'/bar': {
component: Bar
}
})
// Now we can start the app!
// The router will create an instance of App and mount to
// the element matching the selector #app.
router.start(App, '#app')
I also tested it with
Vue.component('Foo', {
template: require('./components/test.vue')
})
In my test.vue i have
<template>
<h2>Test</h2>
</template>
But not as soon as i use require i get everytime the error Required is not defined in my dev tools.
What do i wrong here?
require is a builtin in the NodeJS environment and used in Grunt build environments.
If you also want to use it in a browser environment you can integrate this version of it: http://requirejs.org
(Author) This is outdated:
Use Browserify or Webpack as there is active support in the Vue community
http://vuejs.org/guide/application.html#Deploying_for_Production (dead link)
I personally used this repo of the Vue GitHub-org to get started quickly.
Edit:
This has moved on a bit in early 2018.
Deployment guide: https://v2.vuejs.org/v2/guide/deployment.html
'getting started' type repo: https://github.com/vuejs/vue-loader