declare global {
    type Prop<T, Default extends T | undefined = undefined> = Default extends T ? T : (T | undefined)
}

/** with default **/
declare let modelValue: Prop<number, 0>

/** that prop is required: false **/
declare const show: Prop<boolean>

/** that prop is required: true **/
declare const title: string

const inc = () => {
    modelValue += 1
}

/** expose */
export const dec = () => {
    modelValue -= 1
}

/** render **/
export default () => <div title={title} onClick={inc}>{modelValue}</div>