Develop Reference

Is there a way to encapsulate Vuex store inside Vue plugin (its install function)?

I have a plugin and this plugin uses Vuex
// plugin.js
import Vuex from "vuex";
import store from "./store.js";
export default {
install(Vue, options) {
const storeInstance = new Vuex.Store(store);
Vue.prototype.$store = storeInstance;
}
};
And in that plugin I import a store object.
// store.js
export default {
actions: {
SOME_RANDOM_ACTION({ state, commit }) {
console.log("some random action");
}
}
};
Dispatching actions and using state is fine and works as expected.
But when I add this plugin to another Vue instance that uses vuex, store object re-initializes with new state.
// index.js
import Vue from "vue";
import Vuex from "vuex";
import App from "./App.vue";
import plugin from "./plugin.js";
Vue.use(Vuex);
Vue.use(plugin);
new Vue({
// WARN when i uncomment this next line of code Vuex gets re-initialized with new object
// store: new Vuex.Store({ state: { hello: "hix" } }),
components: {
App
}
}).$mount("#app");
When you uncomment store initialization, store that was defined in the plugin is now not available.
Currently, I have these solutions in mind:
Export my plugin store object to index.js main app, and use this store as a module.
Use some other state management.
Is there a way to use Vuex inside my plugin?
https://codesandbox.io/s/vibrant-sanne-67yej?file=/src/main.js:0-371

Vuex plugin uses store option to assign store instance to Vue.prototype.$store, similarly to your own plugin.
If the intention is to use multiple stores, their names shouldn't collide. The key is to name your store object inside plugin something other than $store
Vue.prototype.$myPluginStore = storeInstance;
But this still doesn't encapsulate $myPluginStore inside the plugin, as it is accessible within the app.
// App.vue
computed: {
appState() {
return this.$store.state;
},
pluginState() {
return this.$myPluginStore.state; // this is now accessible within the main app
}
}
It would be a reasonable solution to allow a store to be used as a module of existing store instead of creating a new store, but only when used within one app and not when used as a plugin for a package.
The main problem is that default store instance ($store) can make use of Vuex helpers - mapGetters, etc.

You can take advantage of the install method exposed by the plugin to get access to the store - which should be accessible from your other component.
One possible solution is to register your store in the index.js like:
import Vue from "vue";
import App from "./App.vue";
import store from "./store";
import plugin from "./plugin";
Vue.use(plugin);
new Vue({
store,
components: {
App
}
}).$mount("#app");
You can then expose $doStuff() and get access to $store in the plugin.js
export default {
install(Vue) {
Vue.prototype.$doStuff = function (payload) {
this.$store.dispatch("SOME_RANDOM_ACTION", payload);
};
}
};
The store instance is accessible from your plugin or all the other components.
You can see a working sample here

Vuejs : use imported plugin mixin localy

Is it possible to use a mixin imported from a VueJS plugin in one component?
I've created a plugin and when I import it I can access the mixin's functions from all my components.
Is there a way to make it available in only one component ? or all the plugin add global-level functionality to Vue by definition?

IMHO you should use create 2 things:
the plugin that imports the essentials globally
the mixin that needs to be imported in the components you want
example:
//main.js
import {MyPlugin} from 'my-library'
vue.use(MyPlugin)
in the component
//component.vue
import {MyMixin} from 'my-library'
export default {
mixins: [myMixin],
}

You can register a mixin either globally, either locally. If you don't register a mixin globally, it will be only available in components where it is locally registered. So, with local registration, you can make a mixin available in only specific components.
Registering globally: you just need to declare it in the main.js file
Nb: you don't need to register the mixin in components
Vue 2:
// main.js
import myMixin from './mixins/myMixin'
Vue.mixin(myMixin) // makes the plugin globally available
new Vue({
// ...
}).$mount('#app')
Vue 3:
// main.js
import myMixin from './mixins/myMixin'
const app = createApp(App)
app.mixin(myMixin) // makes the plugin globally available
app.mount('#app')
Registering locally: you do NOT declare it in the main.js file, and you register the mixin in the relevant components
// componentWithMixin.vue
import myMixins from "../mixins/myMixin"
export default {
// ...
mixins: [myMixins] // importing the mixin - without this line, the mixin can't be available
}

Add global variable in Vue.js 3

Anybody know how to do add a global variable in Vue 3 ?
in Vue 2 we use this in the main.js file:
Vue.prototype.$myGlobalVariable = globalVariable

The most direct replacement is app.config.globalProperties. See:
https://vuejs.org/api/application.html#app-config-globalproperties
So:
Vue.prototype.$myGlobalVariable = globalVariable
becomes:
const app = createApp(RootComponent)
app.config.globalProperties.$myGlobalVariable = globalVariable
This is scoped to a particular application rather than being global as it was with Vue.prototype. This is by design, all 'global' configuration options are now scoped to an application.
The relevant RFC is here:
https://github.com/vuejs/rfcs/blob/master/active-rfcs/0009-global-api-change.md
Properties added to globalProperties will be available via the component instance for all components within the application. So if you're using the Options API you'll be able to access them using this.$myGlobalVariable, just like you could with Vue.prototype. They'll also be available in the template without the this., e.g. {{ $myGlobalVariable }}.
If you're using the Composition API then you'll still be able to use these properties within the template, but you won't have access to the component instance within setup, so these properties won't be accessible there.
While hacks involving getCurrentInstance() can be used to access globalProperties within setup, those hacks involve using undocumented APIs and are not the recommended approach.
Instead, application-level provide/inject (also discussed in that RFC) can be used as an alternative to Vue.prototype:
const app = createApp(RootComponent)
app.provide('myGlobalVariable', globalVariable)
In the descendant component this can then be accessed using inject. e.g. With <script setup>:
<script setup>
import { inject } from 'vue'
const myGlobalVariable = inject('myGlobalVariable')
</script>
Or with an explicit setup function:
import { inject } from 'vue'
export default {
setup() {
const myGlobalVariable = inject('myGlobalVariable')
// Expose it to the template, if required
return {
myGlobalVariable
}
}
}
Or with the Options API:
export default {
inject: ['myGlobalVariable']
}
Docs: https://vuejs.org/api/application.html#app-provide
The idea here is that the component can explicitly declare the property rather than inheriting it by magic. That avoids problems like name collisions, so there's no need to use a $ prefix. It can also help to make it clearer where exactly a property is coming from.
It is common for the inject function to be wrapped in a composable. For example, the useRoute composable exposed by Vue Router is just a wrapper around inject.
In addition to globalProperties and provide/inject, there are various other techniques that might be used to solve the same problems as Vue.prototype. For example, ES modules, stores, or even global mixins. These aren't necessarily direct answers to the specific question posted here, but I've gone into more detail describing the various approaches at:
https://skirtles-code.github.io/vue-examples/patterns/global-properties.html
Which approach you prefer will depend on your circumstances.

How to add a global variable using Vue 3 and vue-cli (or Vite)
Note: You can drop the dollar sign from your $globalVariable and just use globalVariable, just like in the documentation.
Initially your main.js file looks something like this (adding router for common use case):
import { createApp } from 'vue'
import { App } from './App.vue'
import { router } from './router'
createApp(App).use(router).mount('#app')
To use add the global variable using Vue 3 and the vue-cli or Vite:
import { createApp } from 'vue'
import { App } from './App.vue'
import { router } from './router'
// 1. Assign app to a variable
let app = createApp(App)
// 2. Assign the global variable before mounting
app.config.globalProperties.globalVar = 'globalVar'
// 3. Use router and mount app
app.use(router).mount('#app')
Then to access the variables in components like this:
<script>
export default {
data() {
return {
myVar: this.globalVar
}
}
}
</script>
like in the template like this:
<template>
<h1>{{ globalVar }}</h1>
</template>
And that's it. Happy coding!
About Global Variables and Composition API
According to the very bottom of samayo's answer on this post, global variables are only available on the Options API.
Quoting the bottom of his answer:
Note: This is only for the Options API. Evan You (Vue creator) says: "config.globalProperties are meant as an escape hatch for replicating the behavior of Vue.prototype. In setup functions, simply import what you need or explicitly use provide/inject to expose properties to app.

I recommend to use provide/inject approach as follows :
in main.js :
import {createApp} from 'vue'
let app=createApp({
provide:{
globalVariable:123
}
}).$mount('#app')
in some child or grand-child component do :
export default{
name:'some-compo',
inject:['globalVariable'],
//then access this.globalVariable as property in you component
...
}
for composition api and script setup :
import { inject } from 'vue'
let globalVar=inject('globalVariable')

If possible you should use imports or provide/inject. Another way to define global variables/functions and use them would be using globalProperties (although this seems to be considered more of an anti-pattern). But if a library you use uses globalProperties then you can use it like this. This also works with global functions.
const app = Vue.createApp({})
app.config.globalProperties.$http = () => {} // global function
app.config.globalProperties.$globalVariable = 'Jimmy' // global variable
1. Using options API
mounted() {
console.log(this.$globalVariable)
}
2. Using setup method
<script setup>
import { getCurrentInstance } from 'vue'
const app = getCurrentInstance()
const progressBar = app.appContext.config.globalProperties.$globalVariable
console.log(this.$globalVariable)
</script>

For those of you who are confused about how to access globalProperties in the setup() method, you can use getCurrentInstance() as in the following documentation.
https://v3.vuejs.org/api/composition-api.html#getcurrentinstance

In my case I had to create a global var and get the data from a script.
Used provide and inject:
In main.js:
import { createApp } from 'vue'
import App from './App.vue'
const app = createApp(App);
app.provide('message',document.querySelector('script[name="nameSCRIPT"]').innerHTML.split('=').slice(1).join('=').slice(1,-1));
app.mount('#app')
In index.html:
<script name="nameSCRIPT">nameSCRIPT="HELLO"</script>
In child component:
inject:['message'],
mounted(){
console.log(this.message)
},

How to import a js class in main.js file of a vue.js project and use it in all the components instead of importing in each component?

I have written some JS classes that I would like to import in the app.js/main.js file of my vue.js project so that I can instantiate them in the components. Right now I am having to import the same JS class in all the components where I need the class individually.
I've tried the import in the main.js file but the components don't recognize it.
in the main.js file, I am importing like as follows
import Permissions from './Permissions'
However, when I want to instantiate the Permissions class in my component like
data() {
permissions: new Permission({
some object properties...
})
}
the component doesn't know what Permissions is.
How do I let the component know what Permissions class is?

To do it in the vue way, you can create your own plugin or mixin. See detailed instructions here
So, you can create a permissions plugin in permissions-plugin.js
import Permissions from './Permissions'
const PermissionsPlugin = {
install(Vue, options) {
// This adds the $getPermissions method to all instances
Vue.prototype.$getPermissions = function(properties) {
return new Permission({
some object properties...
})
}
}
};
Then you have to tell vue to use your plugin:
import Vue from 'vue'
import PermissionsPlugin from './permissions-plugin.js'
import App from './App.vue'
// The plugin is loaded here.
Vue.use(PermissionsPlugin)
new Vue({
el: '#app',
render: h => h(App)
});
And lastly now from any component you should be able to use your function like:
this.$getPermissions(properties)

Using mixins with Vuejs

I'm currently learning how to develop an app with Vuejs. I have a main.js file with the code for setting up Vue.js. I created a new directory /mixins with a new file api.js. I want to use that as mixin so that every component can use a function to access my api. But I don't know how to do it.
This is my /mixins/api.js file:
export default{
callapi() {
alert('code to call an api');
},
};
This is my main.js file:
import Vue from 'vue';
import VueRouter from 'vue-router';
import VueResource from 'vue-resource';
import { configRouter } from './routeconfig';
import CallAPI from './mixins/api.js';
// Register to vue
Vue.use(VueResource);
Vue.use(VueRouter);
// Create Router
const router = new VueRouter({
history: true,
saveScrollPosition: true,
});
// Configure router
configRouter(router);
// Go!
const App = Vue.extend(
require('./components/app.vue')
);
router.start(App, '#app');
How can I include my mixin the right way now, so that every component has access to the callapi() function?

If you want to use a mixin on a specific component, rather than all components, you can do it like this:
mixin.js
export default {
methods: {
myMethod() { .. }
}
}
component.vue
import mixin from 'mixin';
export default {
mixins: [ mixin ]
}
Another thing you might consider is using a component extension design pattern i.e. creating a base component and then inheriting from that in sub components. It's a little more involved but keeps code DRY if you have many components sharing many options and perhaps inheriting the template too.
I've written about it on my blog if you're interested.

You can apply mixin globally using Vue.mixin
api.js
------
export default {
methods: {
callapi() {};
}
}
main.js
-------
import CallAPI from './mixins/api.js';
Vue.mixin(CallAPI)
As the documentation states you should use it carefully:
Use global mixins sparsely and carefully, because it affects every single Vue instance created, including third party components.