Get elements array sorted by z-index

expand.js

// List
Array.prototype.map.call(
  document.getElementsByTagName('*'),
  (element) => {
    return {
      element: element,
      zIndex: parseInt(getComputedStyle(element)["z-index"])
    }
  }
).filter(
  (item) => !isNaN(item.zIndex)
).sort(
  (a, b) => b.zIndex - a.zIndex
)

// Max only

Array.prototype.map.call(
  document.getElementsByTagName('*'),
  (element) => {
    return {
      element: element,
      zIndex: parseInt(getComputedStyle(element)["z-index"])
    }
  }
).filter(
  (item) => !isNaN(item.zIndex)
).reduce(
  (accumulator, current) => {
    return accumulator.zIndex > current.zIndex ? accumulator : current
  },
  { element: null, element: -1 }
)

maxonly.js

Array.prototype.map.call(document.getElementsByTagName('*'), (element) => { return { element: element, zIndex: parseInt(getComputedStyle(element)["z-index"]) } }).filter((item) => !isNaN(item.zIndex)).reduce((accumulator, current) => { return accumulator.zIndex > current.zIndex ? accumulator : current }, { element: null, element: -1 })

oneline.js

Array.prototype.map.call(document.getElementsByTagName('*'), (element) => { return { element: element, zIndex: parseInt(getComputedStyle(element)["z-index"]) } }).filter((item) => !isNaN(item.zIndex)).sort((a, b) => b.zIndex - a.zIndex)