index.js

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

var SESSIONSTORAGE_PREFIX = 'BackForwardHistory_';

var BackForwardHistory = function () {
  function BackForwardHistory() {
    _classCallCheck(this, BackForwardHistory);

    this.loadStateFromSession();
  }

  _createClass(BackForwardHistory, [{
    key: 'listenTo',
    value: function listenTo(browserHistory) {
      this.browserHistory = browserHistory;
      browserHistory.listen(this.onHistoryEvent.bind(this));
    }
  }, {
    key: 'canGoBack',
    value: function canGoBack() {
      var n = arguments.length <= 0 || arguments[0] === undefined ? 1 : arguments[0];

      return this.currentIndex >= n;
    }
  }, {
    key: 'canGoForward',
    value: function canGoForward() {
      var n = arguments.length <= 0 || arguments[0] === undefined ? 1 : arguments[0];

      return this.currentIndex < this.historyStack.length - n;
    }
  }, {
    key: 'loadStateFromSession',
    value: function loadStateFromSession() {
      this.historyStack = JSON.parse(sessionStorage.getItem(SESSIONSTORAGE_PREFIX + 'historyStack')) || [];
      this.currentIndex = sessionStorage.getItem(SESSIONSTORAGE_PREFIX + 'currentIndex') || 0;
      this.tags = JSON.parse(sessionStorage.getItem(SESSIONSTORAGE_PREFIX + 'tags')) || {};
    }
  }, {
    key: 'saveStateToSession',
    value: function saveStateToSession() {
      sessionStorage.setItem(SESSIONSTORAGE_PREFIX + 'historyStack', JSON.stringify(this.historyStack));
      sessionStorage.setItem(SESSIONSTORAGE_PREFIX + 'currentIndex', this.currentIndex);
      sessionStorage.setItem(SESSIONSTORAGE_PREFIX + 'tags', JSON.stringify(this.tags));
    }
  }, {
    key: 'resetState',
    value: function resetState() {
      this.historyStack = [];
      this.currentIndex = 0;
      this.tags = {};
      this.saveStateToSession();
    }
  }, {
    key: 'onHistoryEvent',
    value: function onHistoryEvent(_ref) {
      var pathname = _ref.pathname;
      var key = _ref.key;
      var action = _ref.action;

      if (this.historyStack.length === 0) {
        this.historyStack.push({ key: key, pathname: pathname });
        return;
      }

      if (action === 'PUSH') {
        if (!this.currentlyOnLastPage) {
          this.historyStack = this.historyStack.splice(0, this.currentIndex + 1);
        }

        this.historyStack.push({ key: key, pathname: pathname });
        this.currentIndex++;
      }

      if (action === 'POP') {
        var potentialIndex = this.getIndexForKey(key);
        if (potentialIndex === -1) {
          // User hit go on url bar. Reset history stack.
          this.resetState();
          this.historyStack = [{ key: key, pathname: pathname }];
        }

        this.currentIndex = this.getIndexForKey(key);
      }

      this.saveStateToSession();
    }
  }, {
    key: 'getIndexForKey',
    value: function getIndexForKey(key) {
      return this.historyStack.findIndex(function (i) {
        return i.key === key;
      });
    }
  }, {
    key: 'getIndexForTag',
    value: function getIndexForTag(tag) {
      return this.getIndexForKey(this.tags[tag]);
    }
  }, {
    key: 'getKeyForTag',
    value: function getKeyForTag(tag) {
      return this.tags[tag];
    }
  }, {
    key: 'getCurrentPathname',
    value: function getCurrentPathname() {
      var n = arguments.length <= 0 || arguments[0] === undefined ? 0 : arguments[0];

      return this.historyStack[this.currentIndex + n].pathname;
    }
  }, {
    key: 'getCurrentLocationTitle',
    value: function getCurrentLocationTitle() {
      var n = arguments.length <= 0 || arguments[0] === undefined ? 0 : arguments[0];

      return this.historyStack[this.currentIndex + n].title;
    }
  }, {
    key: 'getTitleForKey',
    value: function getTitleForKey(key) {
      return this.historyStack[this.getIndexForKey(key)].title;
    }
  }, {
    key: 'setTitleForKey',
    value: function setTitleForKey(key, title) {
      this.historyStack[this.getIndexForKey(key)].title = title;
      this.saveStateToSession();
    }
  }, {
    key: 'setTitleForCurrentLocation',
    value: function setTitleForCurrentLocation(title) {
      var n = arguments.length <= 1 || arguments[1] === undefined ? 0 : arguments[1];

      this.historyStack[this.currentIndex + n].title = title;
      this.saveStateToSession();
    }
  }, {
    key: 'setTagForKey',
    value: function setTagForKey(key, tag) {
      this.tags[tag] = key;
      this.saveStateToSession();
    }
  }, {
    key: 'deleteTag',
    value: function deleteTag(tag) {
      delete this.tags[tag];
      this.saveStateToSession();
    }
  }, {
    key: 'isCurrentlyOnTag',
    value: function isCurrentlyOnTag(tag) {
      return this.currentLocationKey == this.tags[tag];
    }
  }, {
    key: 'goToLocationWithTag',
    value: function goToLocationWithTag(tag) {
      var n = arguments.length <= 1 || arguments[1] === undefined ? 0 : arguments[1];

      var indexOfTag = this.getIndexForTag(tag);
      if (indexOfTag === -1) {
        throw new Error('No index found for tag: ' + tag);
      }

      this.browserHistory.go(indexOfTag - this.currentIndex + n);
    }
  }, {
    key: 'firstLocationKey',
    get: function get() {
      return this.historyStack[0].key;
    }
  }, {
    key: 'currentLocationKey',
    get: function get() {
      return this.historyStack[this.currentIndex].key;
    }
  }, {
    key: 'currentlyOnFirstPage',
    get: function get() {
      return this.currentLocationKey == this.firstLocationKey;
    }
  }, {
    key: 'currentlyOnLastPage',
    get: function get() {
      return !this.canGoForward();
    }
  }]);

  return BackForwardHistory;
}();

exports.default = new BackForwardHistory();