[javascript] Vue template or render function not defined yet I am using neither?

This is my main javascript file:

import Vue from 'vue'

new Vue({
  el: '#app'
});

My HTML file:

<body>
    <div id="app"></div>

    <script src="{{ mix('/js/app.js') }}"></script>
</body>

Webpack configuration of Vue.js with the runtime build:

alias: {
    'vue$': 'vue/dist/vue.runtime.common.js'
}

I am still getting this well known error:

[Vue warn]: Failed to mount component: template or render function not defined. (found in root instance)

How come when I don't even have a single thing inside my #app div where I mount Vue, I am still getting a render/template error? It says found in root but there is nothing to be found because it does not even have any content?

How am I suppose to mount if this does not work?

Edit:

I have tried it like this which seems to work:

new Vue(App).$mount('#app');

It make sense because using the el property implies you are 'scanning' that dom element for any components and it's useless because the runtime build does not have a compiler.

Still it is an extremely strange error message to throw, especially when I have my entire #app div emptied out.

Hopefully somebody could confirm my thoughts.

This question is related to javascript vuejs2 vue-component vue.js

The answer is

I am using Typescript with vue-property-decorator and what happened to me is that my IDE auto-completed "MyComponent.vue.js" instead of "MyComponent.vue". That got me this error.

It seems like the moral of the story is that if you get this error and you are using any kind of single-file component setup, check your imports in the router.

If you used to calle a component like this:

Vue.component('dashboard', require('./components/Dashboard.vue'));

I suppose that problem occurred when you update to laravel mix 5.0 or another libraries, so you have to put .default. As like below:

Vue.component('dashboard', require('./components/Dashboard.vue').default);

I solved the same problem.

In my case, I was using a default import:

import VueAutosuggest from 'vue-autosuggest';

Using a named import fixed it: import {VueAutosuggest} from 'vue-autosuggest';

When used with storybook and typescirpt, I had to add

.storybook/webpack.config.js

const path = require('path');

module.exports = async ({ config, mode }) => {

    config.module.rules.push({
        test: /\.ts$/,
        exclude: /node_modules/,
        use: [
            {
                loader: 'ts-loader',
                options: {
                    appendTsSuffixTo: [/\.vue$/],
                    transpileOnly: true
                },
            }
        ],
    });

    return config;
};

If someone else keeps getting the same error. Just add one extra div in your component template.

As the documentation says:

Component template should contain exactly one root element

Check this simple example:

 import yourComponent from '{path to component}'
    export default {
        components: {
            yourComponent
        },
}

 // Child component
 <template>
     <div> This is the one! </div>
 </template>

My previous code was

Vue.component('message', require('./components/message.vue'));

when i got such errors then i just add .default to it and it worked..

Vue.component('message', require('./components/message.vue').default);

As a Summary of all the posts

This error:

[Vue warn]: Failed to mount component: template or render function not defined.

You're getting because of a certain problem that's preventing your component from being mounted.

This can be caused by a lot of different issues, as you can see from the different posts here. Debug your component thoroughly, and be aware of everything that is maybe not done correctly and might prevent the mount.

_{I was getting the error when my component file was not encoded correctly...}

Something like this should resolve the issue..

Vue.component(
'example-component', 
require('./components/ExampleComponent.vue').default);

Yet another idea to throw in to the mix... In my case, the component throwing the error was a template-less component with a custom render() function. I couldn't see why it wasn't working, until I realised that I hadn't put <script>...</script> tags around the code in the component (seemed unnecessary, since I had no template or style tags either). Not sure why this got past the compiler...?

Either way... make sure you use your <script> tags ;-)

I had this script in app.js in laravel which automatically adds all components in the component folder.

const files = require.context('./', true, /\.vue$/i)
files.keys().map(key => Vue.component(key.split('/').pop().split('.')[0], files(key)))

To make it work just add default

const files = require.context('./', true, /\.vue$/i)
files.keys().map(key => Vue.component(key.split('/').pop().split('.')[0], files(key).default))

I cannot believe how did I fix the issue! weird solution!
I kept the app running then I removed all template tags and again I returned them back and it worked! but I don't understand what happened.

There is an update from Laravel Mix 3 to Laravel 4 which may affect the answer for all components.
See https://laravel-mix.com/docs/4.0/upgrade for more details.

Let 'example-component' be the example component, whose address is './components/ExampleComponent.vue'.

Laravel 3:

 Vue.component('example-component', require('./components/ExampleComponent.vue'));

Laravel 4:

The change is that a .default is added.

 Vue.component('example-component', require('./components/ExampleComponent.vue').default);

I got same error before I forgot to enclose component content in template element.

I have this initially

import Vue from 'vue';
import VueRouter from 'vue-router';
import Home from './com/Home.vue';

Vue.use(VueRouter);

Vue.router = new VueRouter({
    mode: 'history',
    routes: [
        {
            path: '/',
            name: 'home',
            component: Home
        },
    ]
});

Then in Home.vue I have:

<h1>Hello Vue</h1>

Hence the error:

Failed to mount component: template or render function not defined.

found in

---> <Home> at resources/js/com/Home.vue
       <Root>

Enclosing in element fixed the error:

<template>
   <h1>Hello Vue</h1>
</template>

In my case, I was getting the error because I upgraded from Laravel Mix Version 2 to 5.

In Laravel Mix Version 2, you import vue components as follows:

Vue.component(
    'example-component', 
    require('./components/ExampleComponent.vue')
);

In Laravel Mix Version 5, you have to import your components as follows:

import ExampleComponent from './components/ExampleComponent.vue';

Vue.component('example-component', ExampleComponent);

Here is the documentation: https://laravel-mix.com/docs/5.0/upgrade

Better, to improve performance of your app, you can lazy load your components as follows:

Vue.component("ExampleComponent", () => import("./components/ExampleComponent"));

In my case, I imported my component (in router) as:

import bsw from 'common-mod/src/components/webcommon/webcommon'

It is simply solved if I changed it to

import bsw from 'common-mod/src/components/webcommon/webcommon.vue'

Make sure you import the .vue extension explicitly like so:

import myComponent from './my/component/my-component.vue';

If you don't add the .vue and you have a .ts file with the same name in that directory, for example, if you're separating the js/ts from the template and linking it like this inside of my-component.vue:

<script lang="ts" src="./my-component.ts"></script>

... then the import will bring in the .ts by default and so there really is no template or render function defined because it didn't import the .vue template.

When you tell it to use .vue in the import, then it finds your template right away.

I'll add this here b/c there seem to be a number of different reasons why this very frustrating error can appear. In my case, it was a question of syntax in my import statement. I had

import DataTable from '@/components/data-table/DataTable';

when I should have had

import DataTable from '@/components/data-table/';

Your project setup and configuration may vary but if you're getting this error I suggest that you check that the import syntax for your component is as expected for your project.

I personally ran into the same error. None of the above solutions worked for me.

In fact, my component looks like this (in a file called my-component.js) :

Vue.component('my-component', {
    data() {
        return {
            ...
        }
    },
    props: {
        ...
    },
    template:`
        <div>
            ...
        </div>
    `
});

And I imported it like this in another component:

import MyComponent from '{path-to-folder}/my-component';

Vue.component('parent_component', {
    components: {
        MyComponent
    }
});

The weird thing is that this worked in some components but not in this "parent_component". So what I had to do in the component itself was stock it in a variable and export it as default.

const MyComponent = Vue.component('my-component', {
    data() {
        return {
            ...
        }
    },
    props: {
        ...
    },
    template:`
        <div>
            ...
        </div>
    `
});

export default MyComponent;

It could seem obvious but as I said above, it works in 1 other component without this so I couldn't really understand why, but at least, this works everywhere now.

Source: Stackoverflow.com