[Bug] Call typeof in template return Reference Error

[dimar-hanung]

Version

What is expected?

Can call typeof in template

What is actually happening?

Return ReferenceError: _typeof is not defined

Steps to Reproduce

1. Set config following docs
   
2. Call typeof for debugging in template
   
3. This error appear in console, and page doesn't load because this error
   

[JuniorTour]

It is a bug when working with vue-cli.

---

Workaround

1. Exclude @babel/plugin-transform-typeof-symbol from @vue/cli-plugin-babel/preset

// babel.config.js
module.exports = {
    presets: [
        [
            '@vue/cli-plugin-babel/preset',
            {
                exclude: [
                    '@babel/plugin-transform-typeof-symbol'
                ]
            }
        ]
    ],
}

2. Only exclude result of this compiler

// babel.config.js
module.exports = {
  presets: [
    '@vue/cli-plugin-babel/preset'
  ],
  exclude: 'VueTemplateBabelCompiler'
}

---

This compiler take the @vue/cli-plugin-babel/preset as a babel preset by default.

So the typeof keyword is transformed into:

var _typeof = require(".../node_modules/@babel/runtime/helpers/typeof")

// your code...
_typeof example

It is unexpected.

May be we can ignore the default babel.config.js of vue-cli.

---

Do you have interest to fix this issue?
You can:

1. Try to reproduce this code snippet and error by setup DEMO Project.

2. Follow CONTRIBUTING.md to make a Pull Request.

[dimar-hanung]

Thanks for solution and explanation , it's work after exclude '@babel/plugin-transform-typeof-symbol'