"computed" property is called immediately

[mickeyvip]

I am trying to play with the new composition API.

Installed the plugin and copied the "Basic example" from https://vue-composition-api-rfc.netlify.com/#basic-example.

It throws an exception inside the computed getter.

[Vue warn]: Error in setup(): "TypeError: Cannot read property 'count' of undefined"

found in

---> <Counter> at src/components/Counter.vue
       <App> at src/App.vue
         <Root>

The state is declared as follows:

setup() {
    const state = reactive({
      count: 0,
      double: computed(() => state.count * 2)
    })
   //...
}

Am i doing something wrong or is this not supported yet in the plugin?

Thank you.

[doncatnip]

It would seem that the computed property is called immediately, so state is not known yet.
This should work:

  const state = reactive({
    count: 0,
  })
  state.double = computed(() => state.count * 2)

[mickeyvip]

@doncatnip , thank you.

Seems like this plugin is not 100% compliant with the RFC?

[doncatnip]

It certainly isn't. Some shortcomings are documented. This one isn't (if it is indeed one, and not a mistake in the example). It might just be a bug as I would guess computed should only be evaluated on demand.

[mickeyvip]

Got it.

Thank you

[edwardnyc]

您好，我没理解到为什么使用Object.seal可以解决这个问题呢。 可以指导下嘛
@liximomo
Hello, I did not understand why using Object.seal can solve this problem. Can you guide me