Function setup

packages/runtime-dom/__tests__/customElement.spec.ts:79–89

(props, { emit })

        props: ['value'],
        emits: ['update'],
        setup(props, { emit }) {
          return () =>
            h('input', {
              type: 'number',
              value: props.value,
              onInput: (e: InputEvent) => {
                const num = (e.target! as HTMLInputElement).valueAsNumber
                emit('update', Number.isNaN(num) ? null : num)
              },
            })
        },
      })
      customElements.define('my-el-input', CustomInput)
      const num = ref('12')