Version

3.0.6

Reproduction link

https://codesandbox.io/s/pedantic-frog-o34x0?file=/src/App.vue

Steps to reproduce

1、init method 2、change method at data 3、throw error

What is expected?

keep 2.x behavior

What is actually happening?

now is readonly object

@yyx990803 Is it possible to release a version, this issue causes the antdv component library cannot work

@tangjinzhou You can use the nightly build here: https://www.npmjs.com/package/@knightly/vue/v/master