Oops! Vue.js is throwing a compile error involving unused variables and undefined variables

Question

Oops! Vue.js is throwing a compile error involving unused variables and undefined variables

I'm currently working on developing a new Vue.js component, but I'm encountering an error when launching the application. The specific error message is displayed below:

https://i.sstatic.net/0MQxl.png

<template>
    <div class="hello" id="app">
         <span style="font-size:30px;cursor:pointer;" onclick="openNav()">&#9776;</span>

        <div id="mySidenav" class="sidenav">
            <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
            <a href="#">{{name1}}</a>
            <a href="#">{{name2}}</a>
            <a href="#">{{name3}}</a>
            <a href="#">{{name4}}</a>

            <div id="bottom">
                <input v-model="name1" style="margin-left: 25px;max-width: 50%;">
                <input v-model="name2" style="margin-left: 25px;max-width: 50%;">
                <input v-model="name3" style="margin-left: 25px;max-width: 50%;">
                <input v-model="name4" style="margin-left: 25px;max-width: 50%;">
            </div>

        </div>
        ...

</style>

Navigation-Drawer.vue

<template>
  <div id="app">
    <img alt="Vue logo" src="./assets/logo.png">
    <HelloWorld msg="Welcome to Your Vue.js App"/>
    <App msg="test">
  </div>
</template>

<script>
import HelloWorld from './components/HelloWorld.vue'
import App from './components/Navigation-Drawer.vue'
export default {
  name: 'App',
  components: {
    HelloWorld,
    App
  }
}

...

App.vue

javascript vue.js vuejs2

Answer 1

Answer №1

Here are the errors flagged by eslint. For more information, refer to the rules here and here.

To resolve these errors, add the following line just before initializing the app:

// eslint-disable-next-line
var app = new Vue({ 
// additional code

Ensure that the line containing eslint-disable-next-line is commented out. This instructs eslint to skip over that particular line without linting it.

Answer 2

Here are the errors flagged by eslint. For more information, refer to the rules here and here.

To resolve these errors, add the following line just before initializing the app:

// eslint-disable-next-line
var app = new Vue({ 
// additional code

Ensure that the line containing eslint-disable-next-line is commented out. This instructs eslint to skip over that particular line without linting it.

Answer 3

Answer №2

Upon creating the file main.js with CLI, you will find a code snippet similar to this for initializing a new Vue instance:

new Vue({
  render: h => h(App)
}).mount('#app')

Instead of using mount, it might utilize an el property or reference store or router if included during project setup. The crux is that this is where the primary Vue instance is established. Typically, there is no need to redeclare new Vue, especially within a .vue file.

The App mentioned above should correspond to the component within App.vue, which must be imported earlier in main.js.

Now onto App.vue. This line may seem perplexing:

import App from './components/Navigation-Drawer.vue'

While technically correct, it's recommended to rename App to something more coherent like NavigationDrawer. Remember to update all references including the template.

Moving on to Navigation-Drawer.vue, here are a few issues to address.

Firstly, remove the id="app" from the template as it could result in conflicts.

In order to implement onclick="openNav()" in Vue, opt for @click="openNav" and define openNav in the component's methods section.

Your script section should resemble the following:

<script>
    export default {
        name: 'NavigationDrawer',

        props: {
            msg: String
        },

        data () {
            return {
                name1: 'name 1',
                name2: 'name 2',
                name3: 'name 3',
                name4: 'name 4'
            }
        },

        methods: {
            openNav() {
                console.log('openNav called')
            },

            closeNav() {
                console.log('closeNav')
            }
        }
    }
</script>

With these adjustments, everything should function smoothly.

The linting errors originally stemmed from:

Declaration of unused variable app.
Attempt to invoke new Vue without importing Vue. Generally, proper imports are necessary for access within .vue files.

However, resolving these linting errors was secondary to rectifying the aforementioned critical issues.

Answer 4

Upon creating the file main.js with CLI, you will find a code snippet similar to this for initializing a new Vue instance:

new Vue({
  render: h => h(App)
}).mount('#app')

Instead of using mount, it might utilize an el property or reference store or router if included during project setup. The crux is that this is where the primary Vue instance is established. Typically, there is no need to redeclare new Vue, especially within a .vue file.

The App mentioned above should correspond to the component within App.vue, which must be imported earlier in main.js.

Now onto App.vue. This line may seem perplexing:

import App from './components/Navigation-Drawer.vue'

While technically correct, it's recommended to rename App to something more coherent like NavigationDrawer. Remember to update all references including the template.

Moving on to Navigation-Drawer.vue, here are a few issues to address.

Firstly, remove the id="app" from the template as it could result in conflicts.

In order to implement onclick="openNav()" in Vue, opt for @click="openNav" and define openNav in the component's methods section.

Your script section should resemble the following:

<script>
    export default {
        name: 'NavigationDrawer',

        props: {
            msg: String
        },

        data () {
            return {
                name1: 'name 1',
                name2: 'name 2',
                name3: 'name 3',
                name4: 'name 4'
            }
        },

        methods: {
            openNav() {
                console.log('openNav called')
            },

            closeNav() {
                console.log('closeNav')
            }
        }
    }
</script>

With these adjustments, everything should function smoothly.

The linting errors originally stemmed from:

Declaration of unused variable app.
Attempt to invoke new Vue without importing Vue. Generally, proper imports are necessary for access within .vue files.

However, resolving these linting errors was secondary to rectifying the aforementioned critical issues.

Oops! Vue.js is throwing a compile error involving unused variables and undefined variables

Answer №1

Answer №2

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