modern-cpp-tutorial/website/themes/moderncpp/source/modern-cpp/js/common.js

(function () {
  
    initMobileMenu()
    if (PAGE_TYPE) {
      initVersionSelect()
      initSubHeaders()
    }
  
    /**
     * Mobile burger menu button and gesture for toggling sidebar
     */
  
    function initMobileMenu () {
      var mobileBar = document.getElementById('mobile-bar')
      var sidebar = document.querySelector('.sidebar')
      var menuButton = mobileBar.querySelector('.menu-button')
  
      menuButton.addEventListener('click', function () {
        sidebar.classList.toggle('open')
      })
  
      document.body.addEventListener('click', function (e) {
        if (e.target !== menuButton && !sidebar.contains(e.target)) {
          sidebar.classList.remove('open')
        }
      })
  
      // Toggle sidebar on swipe
      var start = {}, end = {}
  
      document.body.addEventListener('touchstart', function (e) {
        start.x = e.changedTouches[0].clientX
        start.y = e.changedTouches[0].clientY
      })
  
      document.body.addEventListener('touchend', function (e) {
        end.y = e.changedTouches[0].clientY
        end.x = e.changedTouches[0].clientX
  
        var xDiff = end.x - start.x
        var yDiff = end.y - start.y
  
        if (Math.abs(xDiff) > Math.abs(yDiff)) {
          if (xDiff > 0 && start.x <= 80) sidebar.classList.add('open')
          else sidebar.classList.remove('open')
        }
      })
    }
  
    /**
     * Doc version select
     */
  
    function initVersionSelect () {
      // version select
      var versionSelect = document.querySelector('.version-select')
      versionSelect && versionSelect.addEventListener('change', function (e) {
        var version = e.target.value
        var section = window.location.pathname.match(/\/v\d\/(\w+?)\//)[1]
        if (version === 'SELF') return
        window.location.assign(
          'http://' +
          version +
          (version && '.') +
          'changkun.de/' + section + '/'
        )
      })
    }
  
    /**
     * Sub headers in sidebar
     */
  
    function initSubHeaders () {
      var each = [].forEach
      var main = document.getElementById('main')
      var header = document.getElementById('header')
      var sidebar = document.querySelector('.sidebar')
      var content = document.querySelector('.content')
  
      // build sidebar
      var currentPageAnchor = sidebar.querySelector('.sidebar-link.current')
      var contentClasses = document.querySelector('.content').classList
      var isAPIOrStyleGuide = (
        contentClasses.contains('api') ||
        contentClasses.contains('style-guide')
      )
      if (currentPageAnchor || isAPIOrStyleGuide) {
        var allHeaders = []
        var sectionContainer
        if (isAPIOrStyleGuide) {
          sectionContainer = document.querySelector('.menu-root')
        } else {
          sectionContainer = document.createElement('ul')
          sectionContainer.className = 'menu-sub'
          currentPageAnchor.parentNode.appendChild(sectionContainer)
        }
        var headers = content.querySelectorAll('h2')
        if (headers.length) {
          each.call(headers, function (h) {
            sectionContainer.appendChild(makeLink(h))
            var h3s = collectH3s(h)
            allHeaders.push(h)
            allHeaders.push.apply(allHeaders, h3s)
            if (h3s.length) {
              sectionContainer.appendChild(makeSubLinks(h3s, isAPIOrStyleGuide))
            }
          })
        } else {
          headers = content.querySelectorAll('h3')
          each.call(headers, function (h) {
            sectionContainer.appendChild(makeLink(h))
            allHeaders.push(h)
          })
        }
  
        var animating = false
        sectionContainer.addEventListener('click', function (e) {
  
          // Not prevent hashchange for smooth-scroll
          // e.preventDefault()
  
          if (e.target.classList.contains('section-link')) {
            sidebar.classList.remove('open')
            setActive(e.target)
            animating = true
            setTimeout(function () {
              animating = false
            }, 400)
          }
        }, true)
  
        // make links clickable
        allHeaders.forEach(makeHeaderClickable)
  
        smoothScroll.init({
          speed: 400,
          offset: 0
        })
      }
  
      var hoveredOverSidebar = false
      sidebar.addEventListener('mouseover', function () {
        hoveredOverSidebar = true
      })
      sidebar.addEventListener('mouseleave', function () {
        hoveredOverSidebar = false
      })
  
      // listen for scroll event to do positioning & highlights
      window.addEventListener('scroll', updateSidebar)
      window.addEventListener('resize', updateSidebar)
  
      function updateSidebar () {
        var doc = document.documentElement
        var top = doc && doc.scrollTop || document.body.scrollTop
        if (animating || !allHeaders) return
        var last
        for (var i = 0; i < allHeaders.length; i++) {
          var link = allHeaders[i]
          if (link.offsetTop > top) {
            if (!last) last = link
            break
          } else {
            last = link
          }
        }
        if (last)
        setActive(last.id, !hoveredOverSidebar)
      }
  
      function makeLink (h) {
        var link = document.createElement('li')
        window.arst = h
        var text = [].slice.call(h.childNodes).map(function (node) {
          if (node.nodeType === Node.TEXT_NODE) {
            return node.nodeValue
          } else if (['CODE', 'SPAN'].indexOf(node.tagName) !== -1) {
            return node.textContent
          } else {
            return ''
          }
        }).join('').replace(/\(.*\)$/, '')
        link.innerHTML =
          '<a class="section-link" data-scroll href="#' + h.id + '">' +
            htmlEscape(text) +
          '</a>'
        return link
      }
  
      function htmlEscape (text) {
        return text
          .replace(/&/g, '&amp;')
          .replace(/"/g, '&quot;')
          .replace(/'/g, '&#39;')
          .replace(/</g, '&lt;')
          .replace(/>/g, '&gt;')
      }
  
      function collectH3s (h) {
        var h3s = []
        var next = h.nextSibling
        while (next && next.tagName !== 'H2') {
          if (next.tagName === 'H3') {
            h3s.push(next)
          }
          next = next.nextSibling
        }
        return h3s
      }
  
      function makeSubLinks (h3s, small) {
        var container = document.createElement('ul')
        if (small) {
          container.className = 'menu-sub'
        }
        h3s.forEach(function (h) {
          container.appendChild(makeLink(h))
        })
        return container
      }
  
      function setActive (id, shouldScrollIntoView) {
        var previousActive = sidebar.querySelector('.section-link.active')
        var currentActive = typeof id === 'string'
          ? sidebar.querySelector('.section-link[href="#' + id + '"]')
          : id
        if (currentActive !== previousActive) {
          if (previousActive) previousActive.classList.remove('active')
          currentActive.classList.add('active')
          if (shouldScrollIntoView) {
            var currentPageOffset = currentPageAnchor
              ? currentPageAnchor.offsetTop - 8
              : 0
            var currentActiveOffset = currentActive.offsetTop + currentActive.parentNode.clientHeight
            var sidebarHeight = sidebar.clientHeight
            var currentActiveIsInView = (
              currentActive.offsetTop >= sidebar.scrollTop &&
              currentActiveOffset <= sidebar.scrollTop + sidebarHeight
            )
            var linkNotFurtherThanSidebarHeight = currentActiveOffset - currentPageOffset < sidebarHeight
            var newScrollTop = currentActiveIsInView
              ? sidebar.scrollTop
              : linkNotFurtherThanSidebarHeight
                ? currentPageOffset
                : currentActiveOffset - sidebarHeight
            sidebar.scrollTop = newScrollTop
          }
        }
      }
  
      function makeHeaderClickable (link) {
        var wrapper = document.createElement('a')
        wrapper.href = '#' + link.id
        wrapper.setAttribute('data-scroll', '')
        link.parentNode.insertBefore(wrapper, link)
        wrapper.appendChild(link)
      }
    }
  })()