<script>
import { computed, reactive, ref } from 'vue'

export default {
  name: 'Child',

  setup() {
    const answer = ref(42)

    const doubleAnswer = computed(() => answer.value * 2)

    const reactiveObject = reactive({
      foo: 'bar',
      hello: {
        world: 1,
      },
      nil: undefined,
      nestedRef: ref('meow'),
      nestedComputed: computed(() => answer.value * 4),
      map: new Map(),
    })

    reactiveObject.map.set('foo', ref('bar'))

    function myMethodFromSetup() {
      console.log('foobar')
    }

    const internalComputed = ref(0)

    const writableComputed = computed({
      get: () => internalComputed.value,
      set: (value) => {
        internalComputed.value = value
      },
    })

    return {
      answer,
      doubleAnswer,
      reactiveObject,
      myMethodFromSetup,
      writableComputed,
    }
  },

  data() {
    return {
      classicAnswer: 42,
    }
  },

  computed: {
    classicDoubleAnswer() {
      return this.classicAnswer * 2
    },

    classicEditableComputed: {
      get() {
        return this.classicAnswer
      },
      set(value) {
        this.classicAnswer = value
      },
    },
  },

  mounted() {
    this.$emit('child mounted', 'bar')
  },
}
</script>

<template>
  <div>
    Child: {{ answer }} x2: {{ doubleAnswer }} x4: {{ reactiveObject.nestedComputed }}
    <button @click="answer *= 2">
      double it
    </button>
    <button @click="answer--">
      minus one
    </button>
  </div>
</template>
