After importing my Vue3 app, I encountered issues with using the app.component function

Question

After importing my Vue3 app, I encountered issues with using the app.component function

In my Vue 3 application, the entry point is main.js:

import { createApp } from 'vue'
import router from './router'
import App from './App.vue'
const app = createApp(App)
app.use(router)
app.mount('#app')
// When I do console.log(app), I see that my app is correctly initialized
export default app

In a separate file called index.js:

import app from '../renderer/src/main.js'
console.log(app)
//...rest of code where I need to use app.component()

An error occurs: ReferenceError: Cannot access 'app' before initialization.

I have verified the paths and they are correct. As stated in the main.js code snippet, my app is indeed initialized as confirmed by the console.log output. However, there seems to be an issue with exporting it properly. My objective is to utilize app.component() and app.use() in another file seamlessly.

javascript vue.js vuejs3

Answer 1

Answer №1

Encountering an issue with importing the app may suggest a potential circular dependency or project configuration problem resulting from multiple source roots. Typically, in a basic setup, there is only one main src folder at the project root; any deviation would require extra setup.

This design challenge is not specific to Vue alone.

If the application instance needs to be reused without triggering circular dependencies and avoiding the use of mount, it might be necessary to extract it into a separate module that can be imported in entry points like so:

import app from '.../my-app';
app.mount(...);

The contents of my-app could be transformed into a function for better reusability. However, in Vue, a reusable component of the application is commonly referred to as a plugin. Essentially, it is a function that takes the application instance and performs various tasks such as installing plugins and registering global components—a process usually between const app = ... and app.mount(...).

In this particular scenario:

export default function myAppPlugin(app, options) {
  app.use(router);
  ...
}

In any subsequent entry point requiring this logic to be reused:

import { createApp } from 'vue'
import App from './App.vue'
import myAppPlugin from '.../my-app-plugin';
const app = createApp(App)
app.use(myAppPlugin);
app.mount('#app');

Answer 2

Encountering an issue with importing the app may suggest a potential circular dependency or project configuration problem resulting from multiple source roots. Typically, in a basic setup, there is only one main src folder at the project root; any deviation would require extra setup.

This design challenge is not specific to Vue alone.

If the application instance needs to be reused without triggering circular dependencies and avoiding the use of mount, it might be necessary to extract it into a separate module that can be imported in entry points like so:

import app from '.../my-app';
app.mount(...);

The contents of my-app could be transformed into a function for better reusability. However, in Vue, a reusable component of the application is commonly referred to as a plugin. Essentially, it is a function that takes the application instance and performs various tasks such as installing plugins and registering global components—a process usually between const app = ... and app.mount(...).

In this particular scenario:

export default function myAppPlugin(app, options) {
  app.use(router);
  ...
}

In any subsequent entry point requiring this logic to be reused:

import { createApp } from 'vue'
import App from './App.vue'
import myAppPlugin from '.../my-app-plugin';
const app = createApp(App)
app.use(myAppPlugin);
app.mount('#app');

Answer 3

Answer №2

There is a alternative approach that can be taken, for instance:
script.js

import { createApp } from 'vue'
import router from './router'
import App from './App.vue'
import { initializeApp, sampleFunction } from "./file.js" // Remember this is your file
const application = createApp(App)
application.use(router)
application.mount('#app')

initializeApp(application);
sampleFunction();

file.js

let application;
export function initializeApp(_application) {
  application = _application
}

// Utilizing the application within this module as well
export function sampleFunction() {
  console.log(application)
}

Answer 4

There is a alternative approach that can be taken, for instance:
script.js

import { createApp } from 'vue'
import router from './router'
import App from './App.vue'
import { initializeApp, sampleFunction } from "./file.js" // Remember this is your file
const application = createApp(App)
application.use(router)
application.mount('#app')

initializeApp(application);
sampleFunction();

file.js

let application;
export function initializeApp(_application) {
  application = _application
}

// Utilizing the application within this module as well
export function sampleFunction() {
  console.log(application)
}

After importing my Vue3 app, I encountered issues with using the app.component function

Answer №1

Answer №2

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