Add title with URL for browsers that hide the URL on hover

fe.ts

export function $$<T extends HTMLElement = HTMLElement>(selector: string) {
  return document.querySelectorAll<T>(selector)
}

export function blank(o: any): o is undefined {
  if (o == null) return true
  const s = String(o)
  return s.length === 0 || s.trim().length === 0
}

export type Maybe<T> = T | undefined
export type MaybeNull<T> = Maybe<T> | null | void

export function map<T, U>(obj: MaybeNull<T>, f: (t: T) => U): Maybe<U> {
  return obj == null ? undefined : f(obj)
}
  
for (const ea of $$("a[target]")) {
  map(ea.getAttribute("href"), href => {
    if (blank(ea.getAttribute("title"))) {
      ea.setAttribute("title", `Click to open ${href} in a new window`)
    }
  })
}