ratchet/lib/js/push.js

/* ----------------------------------
 * PUSH v1.0.0
 * Licensed under The MIT License
 * inspired by chris's jquery.pjax.js
 * http://opensource.org/licenses/MIT
 * ---------------------------------- */

!function () {
  "use strict";
  var noop = function () {};

  // Pushstate cacheing
  // ==================

  var isScrolling,
    maxCacheLength = 20,
    cacheMapping = sessionStorage,
    domCache = {},
    transitionMap = {
      'slide-in': 'slide-out',
      'slide-out': 'slide-in',
      'fade': 'fade'
    },
    bars = {
      bartab: '.bar-tab',
      bartitle: '.bar-title',
      barfooter: '.bar-footer',
      barheadersecondary: '.bar-header-secondary'
    };

  var cacheReplace = function (data, updates) {
    PUSH.id = data.id;
    if (updates) {
      data = getCached(data.id);
    }
    cacheMapping[data.id] = JSON.stringify(data);
    window.history.replaceState(data.id, data.title, data.url);
    domCache[data.id] = document.body.cloneNode(true);
  };

  var cachePush = function () {
    var id = PUSH.id,
      cacheForwardStack = JSON.parse(cacheMapping.cacheForwardStack || '[]'),
      cacheBackStack = JSON.parse(cacheMapping.cacheBackStack || '[]');

    cacheBackStack.push(id);

    while (cacheForwardStack.length) {
      delete cacheMapping[cacheForwardStack.shift()];
    }
    while (cacheBackStack.length > maxCacheLength) {
      delete cacheMapping[cacheBackStack.shift()];
    }

    window.history.pushState(null, '', cacheMapping[PUSH.id].url);

    cacheMapping.cacheForwardStack = JSON.stringify(cacheForwardStack);
    cacheMapping.cacheBackStack = JSON.stringify(cacheBackStack);
  };

  var cachePop = function (id, direction) {
    var forward = direction === 'forward',
      cacheForwardStack = JSON.parse(cacheMapping.cacheForwardStack || '[]'),
      cacheBackStack = JSON.parse(cacheMapping.cacheBackStack || '[]'),
      pushStack = forward ? cacheBackStack : cacheForwardStack,
      popStack = forward ? cacheForwardStack : cacheBackStack;

    if (PUSH.id) {
      pushStack.push(PUSH.id);
    }
    popStack.pop();

    cacheMapping.cacheForwardStack = JSON.stringify(cacheForwardStack);
    cacheMapping.cacheBackStack = JSON.stringify(cacheBackStack);
  };

  var getCached = function (id) {
    return JSON.parse(cacheMapping[id] || null) || {};
  };

  var getTarget = function (e) {
    var target = findTarget(e.target);

    if (!target || (e.which > 1) || e.metaKey || e.ctrlKey || isScrolling || (location.protocol !== target.protocol) || (location.host !== target.host) || (!target.hash && /#/.test(target.href)) || (target.hash && target.href.replace(target.hash, '') === location.href.replace(location.hash, '')) || (target.getAttribute('data-ignore') === 'push')) {
      return;
    }

    return target;
  };


  // Main event handlers (touchend, popstate)
  // ==========================================

  var touchend = function (e) {
    var target = getTarget(e);

    if (!target) {
      return;
    }

    e.preventDefault();

    PUSH({
      url: target.href,
      hash: target.hash,
      timeout: target.getAttribute('data-timeout'),
      transition: target.getAttribute('data-transition')
    });
  };

  var popstate = function (e) {
    var key,
      barElement,
      activeObj,
      activeDom,
      direction,
      transition,
      transitionFrom,
      transitionFromObj,
      id = e.state;

    if (!id || !cacheMapping[id]) {
      return;
    }

    direction = (PUSH.id < id) ? 'forward' : 'back';

    cachePop(id, direction);

    activeObj = getCached(id);
    activeDom = domCache[id];

    if (activeObj.title) {
      document.title = activeObj.title;
    }

    if (direction === 'back') {
      transitionFrom = JSON.parse((direction === 'back') ? cacheMapping.cacheForwardStack : cacheMapping.cacheBackStack);
      transitionFromObj = getCached(transitionFrom[transitionFrom.length - 1]);
    } else {
      transitionFromObj = activeObj;
    }

    if (direction === 'back' && !transitionFromObj.id) {
      return id;
    }

    transition = (direction === 'back') ? transitionMap[transitionFromObj.transition] : transitionFromObj.transition;

    if (!activeDom) {
      return PUSH({
        id: activeObj.id,
        url: activeObj.url,
        title: activeObj.title,
        timeout: activeObj.timeout,
        transition: transition,
        ignorePush: true
      });
    }

    if (transitionFromObj.transition) {
      activeObj = extendWithDom(activeObj, '.content', activeDom.cloneNode(true));
      for (key in bars) {
        barElement = document.querySelector(bars[key]);
        if (activeObj[key]) {
          swapContent(activeObj[key], barElement);
        } else if (barElement) {
          barElement.parentNode.removeChild(barElement);
        }
      }
    }

    swapContent(
    (activeObj.contents || activeDom).cloneNode(true),
      document.querySelector('.content'),
      transition);

    PUSH.id = id;

    document.body.offsetHeight; // force reflow to prevent scroll
  };


  // Core PUSH functionality
  // =======================

  var PUSH = function (options) {
    var key,
      data = {},
      xhr = PUSH.xhr;

    options.container = options.container || options.transition ? document.querySelector('.content') : document.body;

    for (key in bars) {
      options[key] = options[key] || document.querySelector(bars[key]);
    }

    if (xhr && xhr.readyState < 4) {
      xhr.onreadystatechange = noop;
      xhr.abort()
    }

    xhr = new XMLHttpRequest();
    xhr.open('GET', options.url, true);
    xhr.setRequestHeader('X-PUSH', 'true');

    xhr.onreadystatechange = function () {
      if (options._timeout) clearTimeout(options._timeout);
      if (xhr.readyState === 4) {
        (xhr.status === 200) ? success(xhr, options) : failure(options.url);
      }
    };

    if (!PUSH.id) {
      cacheReplace({
        id: +new Date,
        url: window.location.href,
        title: document.title,
        timeout: options.timeout,
        transition: null
      });
    }

    if (options.timeout) {
      options._timeout = setTimeout(function () {
        xhr.abort('timeout');
      }, options.timeout);
    }

    xhr.send();

    if (xhr.readyState && !options.ignorePush) cachePush();
  };


  // Main XHR handlers
  // =================

  var success = function (xhr, options) {
    var key;
    var barElement;
    var data = parseXHR(xhr, options);

    if (!data.contents) return locationReplace(options.url);

    if (data.title) document.title = data.title;

    if (options.transition) {
      for (key in bars) {
        barElement = document.querySelector(bars[key])
        if (data[key]) swapContent(data[key], barElement);
        else if (barElement) barElement.parentNode.removeChild(barElement);
      }
    }

    swapContent(data.contents, options.container, options.transition, function () {
      cacheReplace({
        id: options.id || +new Date,
        url: data.url,
        title: data.title,
        timeout: options.timeout,
        transition: options.transition
      }, options.id);
      triggerStateChange();
    });

    if (!options.ignorePush && window._gaq) _gaq.push(['_trackPageview']) // google analytics
    if (!options.hash) return;
  };

  var failure = function (url) {
    throw new Error('Could not get: ' + url)
  };


  // PUSH helpers
  // ============

  var swapContent = function (swap, container, transition, complete) {
    "use strict";

    function fadeContainerEnd() {
      container.removeEventListener('webkitTransitionEnd', fadeContainerEnd);
      swap.classList.add('in');
      swap.addEventListener('webkitTransitionEnd', fadeSwapEnd);
    }

    function fadeSwapEnd() {
      swap.removeEventListener('webkitTransitionEnd', fadeSwapEnd);
      container.parentNode.removeChild(container);
      swap.classList.remove('fade');
      swap.classList.remove('in');
      complete && complete();
    }

    function slideEnd() {
      swap.removeEventListener('webkitTransitionEnd', slideEnd);
      swap.classList.remove('slide');
      swap.classList.remove(swapDirection);
      container.parentNode.removeChild(container);
      complete && complete();
    }
    var enter,
      containerDirection,
      swapDirection;

    if (!transition) {
      if (container) container.innerHTML = swap.innerHTML;
      else if (swap.classList.contains('content')) document.body.appendChild(swap);
      else document.body.insertBefore(swap, document.querySelector('.content'));
    } else {
      enter = /in$/.test(transition);

      if (transition === 'fade') {
        container.classList.add('in');
        container.classList.add('fade');
        swap.classList.add('fade');
      }

      if (/slide/.test(transition)) {
        swap.classList.add(enter ? 'right' : 'left');
        swap.classList.add('slide');
        container.classList.add('slide');
      }

      container.parentNode.insertBefore(swap, container);
    }

    if (!transition) {
      complete && complete();
    }

    if (transition === 'fade') {
      container.offsetWidth; // force reflow
      container.classList.remove('in');
      container.addEventListener('webkitTransitionEnd', fadeContainerEnd);
    }

    if (/slide/.test(transition)) {
      container.offsetWidth; // force reflow
      swapDirection = enter ? 'right' : 'left'
      containerDirection = enter ? 'left' : 'right'
      container.classList.add(containerDirection);
      swap.classList.remove(swapDirection);
      swap.addEventListener('webkitTransitionEnd', slideEnd);
    }
  };

  var triggerStateChange = function () {
    var e = new CustomEvent('push', {
      detail: {
        state: getCached(PUSH.id)
      },
      bubbles: true,
      cancelable: true
    });

    window.dispatchEvent(e);
  };

  var findTarget = function (target) {
    var i, toggles = document.querySelectorAll('a');
    for (; target && target !== document; target = target.parentNode) {
      for (i = toggles.length; i--;) {
        if (toggles[i] === target) return target;
      }
    }
  };

  var locationReplace = function (url) {
    window.history.replaceState(null, '', '#');
    window.location.replace(url);
  };

  var parseURL = function (url) {
    var a = document.createElement('a');
    a.href = url;
    return a;
  };

  var extendWithDom = function (obj, fragment, dom) {
    var i;
    var result = {};

    for (i = 0; i < obj.length; i += 1) {
      result[i] = obj[i];
    }

    Object.keys(bars).forEach(function (key) {
      var el = dom.querySelector(bars[key]);
      if (el) el.parentNode.removeChild(el);
      result[key] = el;
    });

    result.contents = dom.querySelector(fragment);

    return result;
  };

  var parseXHR = function (xhr, options) {
    var head,
      body,
      data = {},
      responseText = xhr.responseText;

    data.url = options.url;

    if (!responseText) {
      return data;
    }

    if (/<html/i.test(responseText)) {
      head = document.createElement('div');
      body = document.createElement('div');
      head.innerHTML = responseText.match(/<head[^>]*>([\s\S.]*)<\/head>/i)[0]
      body.innerHTML = responseText.match(/<body[^>]*>([\s\S.]*)<\/body>/i)[0]
    } else {
      head = body = document.createElement('div');
      head.innerHTML = responseText;
    }

    data.title = head.querySelector('title');
    data.title = data.title && data.title.innerText.trim();

    if (options.transition) {
      data = extendWithDom(data, '.content', body);
    } else {
      data.contents = body;
    }

    return data;
  };


  // Attach PUSH event handlers
  // ==========================

  window.addEventListener('touchstart', function () {
    isScrolling = false;
  });
  window.addEventListener('touchmove', function () {
    isScrolling = true;
  })
  window.addEventListener('touchend', touchend);
  window.addEventListener('click', function (e) {
    if (getTarget(e)) e.preventDefault();
  });
  window.addEventListener('popstate', popstate);

}();