Vue-next: Mixins for setup method

[NMFES]

What problem does this feature solve?

Is there ability to use common mixin file with setup method for several components?

// mixin.js

export default {
    setup: => { console.log(123); }
}

// component.js

import mixin from 'mixin.js';
export default {
    mixins: [mixin], // <- "setup is not available, but data-property or any other methods work"
}

What does the proposed API look like?

idk

[posva]

I don't think there is a way but it wouldn't make sense because
instead you could create a function that returns
refs and methods and call it inside setup. This way you get typings and things are explicit.
For global mixins you can still use the options api

[sqal]

mixins accepts an array of partial component's options so you should wrap your fn in the methods object in order to be correctly merged:

export default {
   methods: {
     setup() { console.log(123); }
  }
}

other alternatives:

// shared

export const foo = () => {}
export const bar  = () => {}

// component

import { foo, bar } from 'path/to/shared'

export default {
   methods: {
     foo,
     bar,
  }
}

// or put it in the setup hook

export default {
  setup() {
    return {
      foo,
      bar,
    }
  }
}

Vue 2 docs about mixins - https://vuejs.org/v2/guide/mixins.html

[yyx990803]

This is intentional. mixins is a part of the Options API and setup is part of the Composition API. If you are using the Composition API, all logic composition should be done using Composition API.