Version

3.0.0

Reproduction link

https://codepen.io/lolmedo/pen/qBZvxpQ

Steps to reproduce

VueJS 3 project created with Vue CLI, edited with Visual Studio Code.

This code: export default class Home extends Vue { message: string; constructor() { super(); this.message = ""; } }

Produces these runtime error messages in the browser: [Vue warn]: Unhandled error during execution of setup function at <Home onVnodeUnmounted=fn ref=Ref< undefined > > at at runtime-core.esm-bundler.js:38 [Vue warn]: Unhandled error during execution of scheduler flush. This is likely a Vue internals bug. Please open an issue at https://new-issue.vuejs.org/?repo=vuejs/vue-next at <Home onVnodeUnmounted=fn ref=Ref< undefined > > at at runtime-core.esm-bundler.js:38 Uncaught (in promise) TypeError: can't convert undefined to object VueImpl vue-class-component.esm-bundler.js:257 _createSuperInternal Babel Home Home.vue:14 setup vue-class-component.esm-bundler.js:340 callWithErrorHandling runtime-core.esm-bundler.js:154

What is expected?

Being able to use full typescript support with type definitions and variable initialization in the class constructor. This is supported in VueJS v2

What is actually happening?

Getting the following errors on browser: [Vue warn]: Unhandled error during execution of setup function at <Home onVnodeUnmounted=fn ref=Ref< undefined > > at at runtime-core.esm-bundler.js:38 [Vue warn]: Unhandled error during execution of scheduler flush. This is likely a Vue internals bug. Please open an issue at https://new-issue.vuejs.org/?repo=vuejs/vue-next at <Home onVnodeUnmounted=fn ref=Ref< undefined > > at at runtime-core.esm-bundler.js:38 Uncaught (in promise) TypeError: can't convert undefined to object VueImpl vue-class-component.esm-bundler.js:257 _createSuperInternal Babel Home Home.vue:14 setup vue-class-component.esm-bundler.js:340 callWithErrorHandling runtime-core.esm-bundler.js:154

Please open the bug in vue-class-component repository