Turbolinks

turbolinks.js

(function() {
  var anchoredLink, assets, assetsChanged, browserCompatibleDocumentParser, browserSupportsPushState, cacheCurrentPage, changePage, constrainPageCacheTo, createDocument, crossOriginLink, currentState, executeScriptTags, extractAssets, extractLink, extractTitleAndBody, fetchHistory, fetchReplacement, handleClick, ignoreClick, initialized, installClickHandlerLast, intersection, noTurbolink, nonHtmlLink, nonStandardClick, pageCache, recallScrollPosition, referer, reflectNewUrl, reflectRedirectedUrl, rememberCurrentAssets, rememberCurrentState, rememberCurrentUrl, rememberInitialPage, resetScrollPosition, samePageLink, triggerEvent, visit,
    __indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };

  initialized = false;

  currentState = null;

  referer = document.location.href;

  assets = [];

  pageCache = [];

  createDocument = null;

  visit = function(url) {
    if (browserSupportsPushState) {
      cacheCurrentPage();
      reflectNewUrl(url);
      return fetchReplacement(url);
    } else {
      return document.location.href = url;
    }
  };

  fetchReplacement = function(url) {
    var xhr,
      _this = this;
    triggerEvent('page:fetch');
    xhr = new XMLHttpRequest;
    xhr.open('GET', url, true);
    xhr.setRequestHeader('Accept', 'text/html, application/xhtml+xml, application/xml');
    xhr.setRequestHeader('X-XHR-Referer', referer);
    xhr.onload = function() {
      var doc;
      doc = createDocument(xhr.responseText);
      if (assetsChanged(doc)) {
        return document.location.href = url;
      } else {
        changePage.apply(null, extractTitleAndBody(doc));
        reflectRedirectedUrl(xhr);
        resetScrollPosition();
        return triggerEvent('page:load');
      }
    };
    xhr.onabort = function() {
      return console.log('Aborted turbolink fetch!');
    };
    return xhr.send();
  };

  fetchHistory = function(state) {
    var page;
    cacheCurrentPage();
    if (page = pageCache[state.position]) {
      changePage(page.title, page.body);
      recallScrollPosition(page);
      return triggerEvent('page:restore');
    } else {
      return fetchReplacement(document.location.href);
    }
  };

  cacheCurrentPage = function() {
    rememberInitialPage();
    pageCache[currentState.position] = {
      url: document.location.href,
      body: document.body,
      title: document.title,
      positionY: window.pageYOffset,
      positionX: window.pageXOffset
    };
    return constrainPageCacheTo(10);
  };

  constrainPageCacheTo = function(limit) {
    return delete pageCache[currentState.position - limit];
  };

  changePage = function(title, body) {
    document.title = title;
    document.documentElement.replaceChild(body, document.body);
    executeScriptTags();
    currentState = window.history.state;
    return triggerEvent('page:change');
  };

  executeScriptTags = function() {
    var script, _i, _len, _ref, _ref1, _results;
    _ref = document.body.getElementsByTagName('script');
    _results = [];
    for (_i = 0, _len = _ref.length; _i < _len; _i++) {
      script = _ref[_i];
      if ((_ref1 = script.type) === '' || _ref1 === 'text/javascript') {
        _results.push(eval(script.innerHTML));
      }
    }
    return _results;
  };

  reflectNewUrl = function(url) {
    if (url !== document.location.href) {
      referer = document.location.href;
      return window.history.pushState({
        turbolinks: true,
        position: currentState.position + 1
      }, '', url);
    }
  };

  reflectRedirectedUrl = function(xhr) {
    var location;
    if ((location = xhr.getResponseHeader('X-XHR-Current-Location'))) {
      return window.history.replaceState(currentState, '', location);
    }
  };

  rememberCurrentUrl = function() {
    return window.history.replaceState({
      turbolinks: true,
      position: window.history.length - 1
    }, '', document.location.href);
  };

  rememberCurrentState = function() {
    return currentState = window.history.state;
  };

  rememberCurrentAssets = function() {
    return assets = extractAssets(document);
  };

  rememberInitialPage = function() {
    if (!initialized) {
      rememberCurrentUrl();
      rememberCurrentState();
      createDocument = browserCompatibleDocumentParser();
      return initialized = true;
    }
  };

  recallScrollPosition = function(page) {
    return window.scrollTo(page.positionX, page.positionY);
  };

  resetScrollPosition = function() {
    return window.scrollTo(0, 0);
  };

  triggerEvent = function(name) {
    var event;
    event = document.createEvent('Events');
    event.initEvent(name, true, true);
    return document.dispatchEvent(event);
  };

  extractAssets = function(doc) {
    var node, _i, _len, _ref, _results;
    _ref = doc.head.childNodes;
    _results = [];
    for (_i = 0, _len = _ref.length; _i < _len; _i++) {
      node = _ref[_i];
      if (node.src || node.href) {
        _results.push(node.src || node.href);
      }
    }
    return _results;
  };

  assetsChanged = function(doc) {
    return intersection(extractAssets(doc), assets).length !== assets.length;
  };

  intersection = function(a, b) {
    var value, _i, _len, _ref, _results;
    if (a.length > b.length) {
      _ref = [b, a], a = _ref[0], b = _ref[1];
    }
    _results = [];
    for (_i = 0, _len = a.length; _i < _len; _i++) {
      value = a[_i];
      if (__indexOf.call(b, value) >= 0) {
        _results.push(value);
      }
    }
    return _results;
  };

  extractTitleAndBody = function(doc) {
    var title;
    title = doc.querySelector('title');
    return [title != null ? title.textContent : void 0, doc.body];
  };

  browserCompatibleDocumentParser = function() {
    var createDocumentUsingParser, createDocumentUsingWrite, testDoc, _ref;
    createDocumentUsingParser = function(html) {
      return (new DOMParser).parseFromString(html, 'text/html');
    };
    createDocumentUsingWrite = function(html) {
      var doc;
      doc = document.implementation.createHTMLDocument('');
      doc.open('replace');
      doc.write(html);
      doc.close;
      return doc;
    };
    if (window.DOMParser) {
      testDoc = createDocumentUsingParser('<html><body><p>test');
    }
    if ((testDoc != null ? (_ref = testDoc.body) != null ? _ref.childNodes.length : void 0 : void 0) === 1) {
      return createDocumentUsingParser;
    } else {
      return createDocumentUsingWrite;
    }
  };

  installClickHandlerLast = function(event) {
    if (!event.defaultPrevented) {
      document.removeEventListener('click', handleClick);
      return document.addEventListener('click', handleClick);
    }
  };

  handleClick = function(event) {
    var link;
    if (!event.defaultPrevented) {
      link = extractLink(event);
      if (link.nodeName === 'A' && !ignoreClick(event, link)) {
        visit(link.href);
        return event.preventDefault();
      }
    }
  };

  extractLink = function(event) {
    var link;
    link = event.target;
    while (!(link === document || link.nodeName === 'A')) {
      link = link.parentNode;
    }
    return link;
  };

  samePageLink = function(link) {
    return link.href === document.location.href;
  };

  crossOriginLink = function(link) {
    return location.protocol !== link.protocol || location.host !== link.host;
  };

  anchoredLink = function(link) {
    return ((link.hash && link.href.replace(link.hash, '')) === location.href.replace(location.hash, '')) || (link.href === location.href + '#');
  };

  nonHtmlLink = function(link) {
    return link.href.match(/\.[a-z]+(\?.*)?$/g) && !link.href.match(/\.html?(\?.*)?$/g);
  };

  noTurbolink = function(link) {
    var ignore;
    while (!(ignore || link === document)) {
      ignore = link.getAttribute('data-no-turbolink') != null;
      link = link.parentNode;
    }
    return ignore;
  };

  nonStandardClick = function(event) {
    return event.which > 1 || event.metaKey || event.ctrlKey || event.shiftKey || event.altKey;
  };

  ignoreClick = function(event, link) {
    return crossOriginLink(link) || anchoredLink(link) || nonHtmlLink(link) || noTurbolink(link) || nonStandardClick(event);
  };

  browserSupportsPushState = window.history && window.history.pushState && window.history.replaceState && window.history.state !== void 0;

  if (browserSupportsPushState) {
    rememberCurrentAssets();
    document.addEventListener('click', installClickHandlerLast, true);
    window.addEventListener('popstate', function(event) {
      var _ref;
      if ((_ref = event.state) != null ? _ref.turbolinks : void 0) {
        return fetchHistory(event.state);
      }
    });
  }

  this.Turbolinks = {
    visit: visit
  };

}).call(this);