export interface NameDetails {
    username: string
    isMod: boolean
}

export function innermostElement<T extends Element, U extends Element>(
    elem: T
): U {
    if (elem.children.length === 0) {
        // U is the type of the innermost element
        // since we're at the innermost element, we know T = U
        // so we can cast elem (T) to U
        return elem as any as U
    }
    let child = elem.children[0]
    return innermostElement<Element, U>(child)
}

export function elementTreeFind<T extends Element, U extends Element>(
    elem: T,
    fn: (elem: Element) => boolean
): U | null {
    if (fn(elem)) {
        // U is the type of the element that satisfies fn()
        // since we're at the element that satisfies fn(), we know T = U
        // so we can cast elem (T) to U
        return elem as any as U
    }
    if (!elem.parentElement) {
        return null
    }
    return elementTreeFind<Element, U>(elem.parentElement, fn)
}