core/test-dts/defineComponent.test-d.tsx

import {
  describe,
  Component,
  defineComponent,
  PropType,
  ref,
  reactive,
  createApp,
  expectError,
  expectType,
  ComponentPublicInstance,
  ComponentOptions,
  SetupContext,
  IsUnion,
  h
} from './index'

describe('with object props', () => {
  interface ExpectedProps {
    a?: number | undefined
    b: string
    e?: Function
    h: boolean
    bb: string
    bbb: string
    cc?: string[] | undefined
    dd: { n: 1 }
    ee?: () => string
    ff?: (a: number, b: string) => { a: boolean }
    ccc?: string[] | undefined
    ddd: string[]
    eee: () => { a: string }
    fff: (a: number, b: string) => { a: boolean }
    hhh: boolean
    ggg: 'foo' | 'bar'
    ffff: (a: number, b: string) => { a: boolean }
    iii?: (() => string) | (() => number)
    jjj: ((arg1: string) => string) | ((arg1: string, arg2: string) => string)
    kkk?: any
    validated?: string
    date?: Date
  }

  type GT = string & { __brand: unknown }

  const MyComponent = defineComponent({
    props: {
      a: Number,
      // required should make property non-void
      b: {
        type: String,
        required: true
      },
      e: Function,
      h: Boolean,
      // default value should infer type and make it non-void
      bb: {
        default: 'hello'
      },
      bbb: {
        // Note: default function value requires arrow syntax + explicit
        // annotation
        default: (props: any) => (props.bb as string) || 'foo'
      },
      // explicit type casting
      cc: Array as PropType<string[]>,
      // required + type casting
      dd: {
        type: Object as PropType<{ n: 1 }>,
        required: true
      },
      // return type
      ee: Function as PropType<() => string>,
      // arguments + object return
      ff: Function as PropType<(a: number, b: string) => { a: boolean }>,
      // explicit type casting with constructor
      ccc: Array as () => string[],
      // required + contructor type casting
      ddd: {
        type: Array as () => string[],
        required: true
      },
      // required + object return
      eee: {
        type: Function as PropType<() => { a: string }>,
        required: true
      },
      // required + arguments + object return
      fff: {
        type: Function as PropType<(a: number, b: string) => { a: boolean }>,
        required: true
      },
      hhh: {
        type: Boolean,
        required: true
      },
      // default + type casting
      ggg: {
        type: String as PropType<'foo' | 'bar'>,
        default: 'foo'
      },
      // default + function
      ffff: {
        type: Function as PropType<(a: number, b: string) => { a: boolean }>,
        default: (a: number, b: string) => ({ a: a > +b })
      },
      // union + function with different return types
      iii: Function as PropType<(() => string) | (() => number)>,
      // union + function with different args & same return type
      jjj: {
        type: Function as PropType<
          ((arg1: string) => string) | ((arg1: string, arg2: string) => string)
        >,
        required: true
      },
      kkk: null,
      validated: {
        type: String,
        // validator requires explicit annotation
        validator: (val: unknown) => val !== ''
      },
      date: Date
    },
    setup(props) {
      // type assertion. See https://github.com/SamVerschueren/tsd
      expectType<ExpectedProps['a']>(props.a)
      expectType<ExpectedProps['b']>(props.b)
      expectType<ExpectedProps['e']>(props.e)
      expectType<ExpectedProps['h']>(props.h)
      expectType<ExpectedProps['bb']>(props.bb)
      expectType<ExpectedProps['bbb']>(props.bbb)
      expectType<ExpectedProps['cc']>(props.cc)
      expectType<ExpectedProps['dd']>(props.dd)
      expectType<ExpectedProps['ee']>(props.ee)
      expectType<ExpectedProps['ff']>(props.ff)
      expectType<ExpectedProps['ccc']>(props.ccc)
      expectType<ExpectedProps['ddd']>(props.ddd)
      expectType<ExpectedProps['eee']>(props.eee)
      expectType<ExpectedProps['fff']>(props.fff)
      expectType<ExpectedProps['hhh']>(props.hhh)
      expectType<ExpectedProps['ggg']>(props.ggg)
      expectType<ExpectedProps['ffff']>(props.ffff)
      if (typeof props.iii !== 'function') {
        expectType<undefined>(props.iii)
      }
      expectType<ExpectedProps['iii']>(props.iii)
      expectType<IsUnion<typeof props.jjj>>(true)
      expectType<ExpectedProps['jjj']>(props.jjj)
      expectType<ExpectedProps['kkk']>(props.kkk)
      expectType<ExpectedProps['validated']>(props.validated)
      expectType<ExpectedProps['date']>(props.date)

      // @ts-expect-error props should be readonly
      expectError((props.a = 1))

      // setup context
      return {
        c: ref(1),
        d: {
          e: ref('hi')
        },
        f: reactive({
          g: ref('hello' as GT)
        })
      }
    },
    render() {
      const props = this.$props
      expectType<ExpectedProps['a']>(props.a)
      expectType<ExpectedProps['b']>(props.b)
      expectType<ExpectedProps['e']>(props.e)
      expectType<ExpectedProps['h']>(props.h)
      expectType<ExpectedProps['bb']>(props.bb)
      expectType<ExpectedProps['cc']>(props.cc)
      expectType<ExpectedProps['dd']>(props.dd)
      expectType<ExpectedProps['ee']>(props.ee)
      expectType<ExpectedProps['ff']>(props.ff)
      expectType<ExpectedProps['ccc']>(props.ccc)
      expectType<ExpectedProps['ddd']>(props.ddd)
      expectType<ExpectedProps['eee']>(props.eee)
      expectType<ExpectedProps['fff']>(props.fff)
      expectType<ExpectedProps['hhh']>(props.hhh)
      expectType<ExpectedProps['ggg']>(props.ggg)
      if (typeof props.iii !== 'function') {
        expectType<undefined>(props.iii)
      }
      expectType<ExpectedProps['iii']>(props.iii)
      expectType<IsUnion<typeof props.jjj>>(true)
      expectType<ExpectedProps['jjj']>(props.jjj)
      expectType<ExpectedProps['kkk']>(props.kkk)

      // @ts-expect-error props should be readonly
      expectError((props.a = 1))

      // should also expose declared props on `this`
      expectType<ExpectedProps['a']>(this.a)
      expectType<ExpectedProps['b']>(this.b)
      expectType<ExpectedProps['e']>(this.e)
      expectType<ExpectedProps['h']>(this.h)
      expectType<ExpectedProps['bb']>(this.bb)
      expectType<ExpectedProps['cc']>(this.cc)
      expectType<ExpectedProps['dd']>(this.dd)
      expectType<ExpectedProps['ee']>(this.ee)
      expectType<ExpectedProps['ff']>(this.ff)
      expectType<ExpectedProps['ccc']>(this.ccc)
      expectType<ExpectedProps['ddd']>(this.ddd)
      expectType<ExpectedProps['eee']>(this.eee)
      expectType<ExpectedProps['fff']>(this.fff)
      expectType<ExpectedProps['hhh']>(this.hhh)
      expectType<ExpectedProps['ggg']>(this.ggg)
      if (typeof this.iii !== 'function') {
        expectType<undefined>(this.iii)
      }
      expectType<ExpectedProps['iii']>(this.iii)
      const { jjj } = this
      expectType<IsUnion<typeof jjj>>(true)
      expectType<ExpectedProps['jjj']>(this.jjj)
      expectType<ExpectedProps['kkk']>(this.kkk)

      // @ts-expect-error props on `this` should be readonly
      expectError((this.a = 1))

      // assert setup context unwrapping
      expectType<number>(this.c)
      expectType<string>(this.d.e.value)
      expectType<GT>(this.f.g)

      // setup context properties should be mutable
      this.c = 2

      return null
    }
  })

  expectType<Component>(MyComponent)

  // Test TSX
  expectType<JSX.Element>(
    <MyComponent
      a={1}
      b="b"
      bb="bb"
      e={() => {}}
      cc={['cc']}
      dd={{ n: 1 }}
      ee={() => 'ee'}
      ccc={['ccc']}
      ddd={['ddd']}
      eee={() => ({ a: 'eee' })}
      fff={(a, b) => ({ a: a > +b })}
      hhh={false}
      ggg="foo"
      jjj={() => ''}
      // should allow class/style as attrs
      class="bar"
      style={{ color: 'red' }}
      // should allow key
      key={'foo'}
      // should allow ref
      ref={'foo'}
    />
  )

  expectType<Component>(
    <MyComponent
      b="b"
      dd={{ n: 1 }}
      ddd={['ddd']}
      eee={() => ({ a: 'eee' })}
      fff={(a, b) => ({ a: a > +b })}
      hhh={false}
      jjj={() => ''}
    />
  )

  // @ts-expect-error missing required props
  expectError(<MyComponent />)

  expectError(
    // @ts-expect-error wrong prop types
    <MyComponent a={'wrong type'} b="foo" dd={{ n: 1 }} ddd={['foo']} />
  )
  expectError(
    // @ts-expect-error wrong prop types
    <MyComponent ggg="baz" />
  )
  // @ts-expect-error
  expectError(<MyComponent b="foo" dd={{ n: 'string' }} ddd={['foo']} />)

  // `this` should be void inside of prop validators and prop default factories
  defineComponent({
    props: {
      myProp: {
        type: Number,
        validator(val: unknown): boolean {
          // @ts-expect-error
          return val !== this.otherProp
        },
        default(): number {
          // @ts-expect-error
          return this.otherProp + 1
        }
      },
      otherProp: {
        type: Number,
        required: true
      }
    }
  })
})

// describe('type inference w/ optional props declaration', () => {
//   const MyComponent = defineComponent({
//     setup(_props: { msg: string }) {
//       return {
//         a: 1
//       }
//     },
//     render() {
//       expectType<string>(this.$props.msg)
//       // props should be readonly
//       expectError((this.$props.msg = 'foo'))
//       // should not expose on `this`
//       expectError(this.msg)
//       expectType<number>(this.a)
//       return null
//     }
//   })

//   expectType<JSX.Element>(<MyComponent msg="foo" />)
//   expectError(<MyComponent />)
//   expectError(<MyComponent msg={1} />)
// })

// describe('type inference w/ direct setup function', () => {
//   const MyComponent = defineComponent((_props: { msg: string }) => {})
//   expectType<JSX.Element>(<MyComponent msg="foo" />)
//   expectError(<MyComponent />)
//   expectError(<MyComponent msg={1} />)
// })

describe('type inference w/ array props declaration', () => {
  const MyComponent = defineComponent({
    props: ['a', 'b'],
    setup(props) {
      // @ts-expect-error props should be readonly
      expectError((props.a = 1))
      expectType<any>(props.a)
      expectType<any>(props.b)
      return {
        c: 1
      }
    },
    render() {
      expectType<any>(this.$props.a)
      expectType<any>(this.$props.b)
      // @ts-expect-error
      expectError((this.$props.a = 1))
      expectType<any>(this.a)
      expectType<any>(this.b)
      expectType<number>(this.c)
    }
  })
  expectType<JSX.Element>(<MyComponent a={[1, 2]} b="b" />)
  // @ts-expect-error
  expectError(<MyComponent other="other" />)
})

describe('type inference w/ options API', () => {
  defineComponent({
    props: { a: Number },
    setup() {
      return {
        b: 123
      }
    },
    data() {
      // Limitation: we cannot expose the return result of setup() on `this`
      // here in data() - somehow that would mess up the inference
      expectType<number | undefined>(this.a)
      return {
        c: this.a || 123,
        someRef: ref(0)
      }
    },
    computed: {
      d(): number {
        expectType<number>(this.b)
        return this.b + 1
      },
      e: {
        get(): number {
          expectType<number>(this.b)
          expectType<number>(this.d)

          return this.b + this.d
        },
        set(v: number) {
          expectType<number>(this.b)
          expectType<number>(this.d)
          expectType<number>(v)
        }
      }
    },
    watch: {
      a() {
        expectType<number>(this.b)
        this.b + 1
      }
    },
    created() {
      // props
      expectType<number | undefined>(this.a)
      // returned from setup()
      expectType<number>(this.b)
      // returned from data()
      expectType<number>(this.c)
      // computed
      expectType<number>(this.d)
      // computed get/set
      expectType<number>(this.e)
      expectType<number>(this.someRef)
    },
    methods: {
      doSomething() {
        // props
        expectType<number | undefined>(this.a)
        // returned from setup()
        expectType<number>(this.b)
        // returned from data()
        expectType<number>(this.c)
        // computed
        expectType<number>(this.d)
        // computed get/set
        expectType<number>(this.e)
      },
      returnSomething() {
        return this.a
      }
    },
    render() {
      // props
      expectType<number | undefined>(this.a)
      // returned from setup()
      expectType<number>(this.b)
      // returned from data()
      expectType<number>(this.c)
      // computed
      expectType<number>(this.d)
      // computed get/set
      expectType<number>(this.e)
      // method
      expectType<() => number | undefined>(this.returnSomething)
    }
  })
})

describe('with mixins', () => {
  const MixinA = defineComponent({
    props: {
      aP1: {
        type: String,
        default: 'aP1'
      },
      aP2: Boolean
    },
    data() {
      return {
        a: 1
      }
    }
  })
  const MixinB = defineComponent({
    props: ['bP1', 'bP2'],
    data() {
      return {
        b: 2
      }
    }
  })
  const MixinC = defineComponent({
    data() {
      return {
        c: 3
      }
    }
  })
  const MixinD = defineComponent({
    mixins: [MixinA],
    data() {
      //@ts-expect-error computed are not available on data()
      expectError<number>(this.dC1)
      //@ts-expect-error computed are not available on data()
      expectError<string>(this.dC2)

      return {
        d: 4
      }
    },
    setup(props) {
      expectType<string>(props.aP1)
    },
    computed: {
      dC1(): number {
        return this.d + this.a
      },
      dC2(): string {
        return this.aP1 + 'dC2'
      }
    }
  })
  const MyComponent = defineComponent({
    mixins: [MixinA, MixinB, MixinC, MixinD],
    props: {
      // required should make property non-void
      z: {
        type: String,
        required: true
      }
    },

    data(vm) {
      expectType<number>(vm.a)
      expectType<number>(vm.b)
      expectType<number>(vm.c)
      expectType<number>(vm.d)

      // should also expose declared props on `this`
      expectType<number>(this.a)
      expectType<string>(this.aP1)
      expectType<boolean | undefined>(this.aP2)
      expectType<number>(this.b)
      expectType<any>(this.bP1)
      expectType<number>(this.c)
      expectType<number>(this.d)

      return {}
    },

    setup(props) {
      expectType<string>(props.z)
      // props
      expectType<string>(props.aP1)
      expectType<boolean | undefined>(props.aP2)
      expectType<any>(props.bP1)
      expectType<any>(props.bP2)
      expectType<string>(props.z)
    },
    render() {
      const props = this.$props
      // props
      expectType<string>(props.aP1)
      expectType<boolean | undefined>(props.aP2)
      expectType<any>(props.bP1)
      expectType<any>(props.bP2)
      expectType<string>(props.z)

      const data = this.$data
      expectType<number>(data.a)
      expectType<number>(data.b)
      expectType<number>(data.c)
      expectType<number>(data.d)

      // should also expose declared props on `this`
      expectType<number>(this.a)
      expectType<string>(this.aP1)
      expectType<boolean | undefined>(this.aP2)
      expectType<number>(this.b)
      expectType<any>(this.bP1)
      expectType<number>(this.c)
      expectType<number>(this.d)
      expectType<number>(this.dC1)
      expectType<string>(this.dC2)

      // props should be readonly
      // @ts-expect-error
      expectError((this.aP1 = 'new'))
      // @ts-expect-error
      expectError((this.z = 1))

      // props on `this` should be readonly
      // @ts-expect-error
      expectError((this.bP1 = 1))

      // string value can not assigned to number type value
      // @ts-expect-error
      expectError((this.c = '1'))

      // setup context properties should be mutable
      this.d = 5

      return null
    }
  })

  // Test TSX
  expectType<JSX.Element>(
    <MyComponent aP1={'aP'} aP2 bP1={1} bP2={[1, 2]} z={'z'} />
  )

  // missing required props
  // @ts-expect-error
  expectError(<MyComponent />)

  // wrong prop types
  // @ts-expect-error
  expectError(<MyComponent aP1="ap" aP2={'wrong type'} bP1="b" z={'z'} />)
  // @ts-expect-error
  expectError(<MyComponent aP1={1} bP2={[1]} />)
})

describe('with extends', () => {
  const Base = defineComponent({
    props: {
      aP1: Boolean,
      aP2: {
        type: Number,
        default: 2
      }
    },
    data() {
      return {
        a: 1
      }
    },
    computed: {
      c(): number {
        return this.aP2 + this.a
      }
    }
  })
  const MyComponent = defineComponent({
    extends: Base,
    props: {
      // required should make property non-void
      z: {
        type: String,
        required: true
      }
    },
    render() {
      const props = this.$props
      // props
      expectType<boolean | undefined>(props.aP1)
      expectType<number>(props.aP2)
      expectType<string>(props.z)

      const data = this.$data
      expectType<number>(data.a)

      // should also expose declared props on `this`
      expectType<number>(this.a)
      expectType<boolean | undefined>(this.aP1)
      expectType<number>(this.aP2)

      // setup context properties should be mutable
      this.a = 5

      return null
    }
  })

  // Test TSX
  expectType<JSX.Element>(<MyComponent aP2={3} aP1 z={'z'} />)

  // missing required props
  // @ts-expect-error
  expectError(<MyComponent />)

  // wrong prop types
  // @ts-expect-error
  expectError(<MyComponent aP2={'wrong type'} z={'z'} />)
  // @ts-expect-error
  expectError(<MyComponent aP1={3} />)
})

describe('extends with mixins', () => {
  const Mixin = defineComponent({
    props: {
      mP1: {
        type: String,
        default: 'mP1'
      },
      mP2: Boolean,
      mP3: {
        type: Boolean,
        required: true
      }
    },
    data() {
      return {
        a: 1
      }
    }
  })
  const Base = defineComponent({
    props: {
      p1: Boolean,
      p2: {
        type: Number,
        default: 2
      },
      p3: {
        type: Boolean,
        required: true
      }
    },
    data() {
      return {
        b: 2
      }
    },
    computed: {
      c(): number {
        return this.p2 + this.b
      }
    }
  })
  const MyComponent = defineComponent({
    extends: Base,
    mixins: [Mixin],
    props: {
      // required should make property non-void
      z: {
        type: String,
        required: true
      }
    },
    render() {
      const props = this.$props
      // props
      expectType<boolean | undefined>(props.p1)
      expectType<number>(props.p2)
      expectType<string>(props.z)
      expectType<string>(props.mP1)
      expectType<boolean | undefined>(props.mP2)

      const data = this.$data
      expectType<number>(data.a)
      expectType<number>(data.b)

      // should also expose declared props on `this`
      expectType<number>(this.a)
      expectType<number>(this.b)
      expectType<boolean | undefined>(this.p1)
      expectType<number>(this.p2)
      expectType<string>(this.mP1)
      expectType<boolean | undefined>(this.mP2)

      // setup context properties should be mutable
      this.a = 5

      return null
    }
  })

  // Test TSX
  expectType<JSX.Element>(<MyComponent mP1="p1" mP2 mP3 p1 p2={1} p3 z={'z'} />)

  // mP1, mP2, p1, and p2 have default value. these are not required
  expectType<JSX.Element>(<MyComponent mP3 p3 z={'z'} />)

  // missing required props
  // @ts-expect-error
  expectError(<MyComponent mP3 p3 /* z='z' */ />)
  // missing required props from mixin
  // @ts-expect-error
  expectError(<MyComponent /* mP3 */ p3 z="z" />)
  // missing required props from extends
  // @ts-expect-error
  expectError(<MyComponent mP3 /* p3 */ z="z" />)

  // wrong prop types
  // @ts-expect-error
  expectError(<MyComponent p2={'wrong type'} z={'z'} />)
  // @ts-expect-error
  expectError(<MyComponent mP1={3} />)
})

describe('compatibility w/ createApp', () => {
  const comp = defineComponent({})
  createApp(comp).mount('#hello')

  const comp2 = defineComponent({
    props: { foo: String }
  })
  createApp(comp2).mount('#hello')

  const comp3 = defineComponent({
    setup() {
      return {
        a: 1
      }
    }
  })
  createApp(comp3).mount('#hello')
})

describe('defineComponent', () => {
  test('should accept components defined with defineComponent', () => {
    const comp = defineComponent({})
    defineComponent({
      components: { comp }
    })
  })

  test('should accept class components with receiving constructor arguments', () => {
    class Comp {
      static __vccOpts = {}
      constructor(_props: { foo: string }) {}
    }
    defineComponent({
      components: { Comp }
    })
  })
})

describe('emits', () => {
  // Note: for TSX inference, ideally we want to map emits to onXXX props,
  // but that requires type-level string constant concatenation as suggested in
  // https://github.com/Microsoft/TypeScript/issues/12754

  // The workaround for TSX users is instead of using emits, declare onXXX props
  // and call them instead. Since `v-on:click` compiles to an `onClick` prop,
  // this would also support other users consuming the component in templates
  // with `v-on` listeners.

  // with object emits
  defineComponent({
    emits: {
      click: (n: number) => typeof n === 'number',
      input: (b: string) => b.length > 1
    },
    setup(props, { emit }) {
      emit('click', 1)
      emit('input', 'foo')
      //  @ts-expect-error
      expectError(emit('nope'))
      //  @ts-expect-error
      expectError(emit('click'))
      //  @ts-expect-error
      expectError(emit('click', 'foo'))
      //  @ts-expect-error
      expectError(emit('input'))
      //  @ts-expect-error
      expectError(emit('input', 1))
    },
    created() {
      this.$emit('click', 1)
      this.$emit('input', 'foo')
      //  @ts-expect-error
      expectError(this.$emit('nope'))
      //  @ts-expect-error
      expectError(this.$emit('click'))
      //  @ts-expect-error
      expectError(this.$emit('click', 'foo'))
      //  @ts-expect-error
      expectError(this.$emit('input'))
      //  @ts-expect-error
      expectError(this.$emit('input', 1))
    }
  })

  // with array emits
  defineComponent({
    emits: ['foo', 'bar'],
    setup(props, { emit }) {
      emit('foo')
      emit('foo', 123)
      emit('bar')
      //  @ts-expect-error
      expectError(emit('nope'))
    },
    created() {
      this.$emit('foo')
      this.$emit('foo', 123)
      this.$emit('bar')
      //  @ts-expect-error
      expectError(this.$emit('nope'))
    }
  })

  // without emits
  defineComponent({
    setup(props, { emit }) {
      emit('test', 1)
      emit('test')
    }
  })

  // emit should be valid when ComponentPublicInstance is used.
  const instance = {} as ComponentPublicInstance
  instance.$emit('test', 1)
  instance.$emit('test')

  // `this` should be void inside of emits validators
  defineComponent({
    props: ['bar'],
    emits: {
      foo(): boolean {
        // @ts-expect-error
        return this.bar === 3
      }
    }
  })
})

describe('componentOptions setup should be `SetupContext`', () => {
  expect<ComponentOptions['setup']>({} as (
    props: Record<string, any>,
    ctx: SetupContext
  ) => any)
})

describe('extract instance type', () => {
  const Base = defineComponent({
    props: {
      baseA: {
        type: Number,
        default: 1
      }
    }
  })
  const MixinA = defineComponent({
    props: {
      mA: {
        type: String,
        default: ''
      }
    }
  })
  const CompA = defineComponent({
    extends: Base,
    mixins: [MixinA],
    props: {
      a: {
        type: Boolean,
        default: false
      },
      b: {
        type: String,
        required: true
      },
      c: Number
    }
  })

  const compA = {} as InstanceType<typeof CompA>

  expectType<boolean>(compA.a)
  expectType<string>(compA.b)
  expectType<number | undefined>(compA.c)
  // mixins
  expectType<string>(compA.mA)
  // extends
  expectType<number>(compA.baseA)

  //  @ts-expect-error
  expectError((compA.a = true))
  //  @ts-expect-error
  expectError((compA.b = 'foo'))
  //  @ts-expect-error
  expectError((compA.c = 1))
  //  @ts-expect-error
  expectError((compA.mA = 'foo'))
  //  @ts-expect-error
  expectError((compA.baseA = 1))
})

describe('async setup', () => {
  type GT = string & { __brand: unknown }
  const Comp = defineComponent({
    async setup() {
      // setup context
      return {
        a: ref(1),
        b: {
          c: ref('hi')
        },
        d: reactive({
          e: ref('hello' as GT)
        })
      }
    },
    render() {
      // assert setup context unwrapping
      expectType<number>(this.a)
      expectType<string>(this.b.c.value)
      expectType<GT>(this.d.e)

      // setup context properties should be mutable
      this.a = 2
    }
  })

  const vm = {} as InstanceType<typeof Comp>
  // assert setup context unwrapping
  expectType<number>(vm.a)
  expectType<string>(vm.b.c.value)
  expectType<GT>(vm.d.e)

  // setup context properties should be mutable
  vm.a = 2
})

// check if defineComponent can be exported
export default {
  // function components
  a: defineComponent(_ => h('div')),
  // no props
  b: defineComponent({
    data() {
      return {}
    }
  }),
  c: defineComponent({
    props: ['a']
  }),
  d: defineComponent({
    props: {
      a: Number
    }
  })
}