ZwiiCMS/core/vendor/favicon-switcher/favicon-switcher.js

;(function(mod){
    function collectLinks() {
      return Array.prototype.slice.apply(
        document.head.querySelectorAll('link[rel*="icon"]')
      )
    }

    function applyLink(source, target) {
      target.setAttribute('type', source.getAttribute('type'))
      target.setAttribute('href', source.getAttribute('href'))
    }

    // eslint-disable-next-line no-unused-vars
    function initSwitcher(delay) {
      // Exit if media queries aren't supported
      if (typeof window.matchMedia !== 'function') {
        return function noop() {}
      }

      var links = collectLinks()
      var current = document.createElement('link')
      var prevMatch

      current.setAttribute('rel', 'shortcut icon')
      document.head.appendChild(current)

      function faviconApplyLoop() {
        links.forEach(function(link) {
          if (window.matchMedia(link.media).matches) {
            if (link.media !== prevMatch) {
              prevMatch = link.media
              applyLink(link, current)
            }
          }
        })
      }

      var intervalId = setInterval(faviconApplyLoop, delay || 300)

      function unsubscribe() {
        clearInterval(intervalId)
        links.forEach(function(link) {
          document.head.appendChild(link)
        })
      }

      faviconApplyLoop()
      links.forEach(function(link) {
        document.head.removeChild(link)
      })

      return unsubscribe
    }

    initSwitcher()
    })()