old_contents: (function(app) {
    'use strict';
  
    var jCore = require('jcore');
    var helper = app.helper || require('../helper.js');
    var dom = app.dom || require('../dom.js');
  
    var SidebarToggleButton = helper.inherits(function(props) {
      SidebarToggleButton.super_.call(this);
  
      this.type = this.prop(SidebarToggleButton.TYPE_COLLAPSE);
      this.disabled = this.prop(false);
      this.element = this.prop(props.element);
      this.cache = this.prop({});
  
      this.collapser = props.collapser;
      this.expander = props.expander;
    }, jCore.Component);
  
    SidebarToggleButton.prototype.redraw = function() {
      var cache = this.cache();
  
      var type = this.type();
      if (type !== cache.type) {
        dom.data(this.element(), 'type', type);
        cache.type = type;
      }
  
      var disabled = this.disabled();
      if (disabled !== cache.disabled) {
        dom.disabled(this.element(), disabled);
        cache.disabled = disabled;
      }
    };
  
    SidebarToggleButton.TYPE_COLLAPSE = 'collapse';
    SidebarToggleButton.TYPE_EXPAND = 'expand';
  
    var ContentHeader = helper.inherits(function(props) {
      ContentHeader.super_.call(this);
  
      this.element = this.prop(props.element);
  
      this.sidebarToggleButton = this.prop(new SidebarToggleButton({
        element: this.sidebarToggleButtonElement(),
        collapser: props.sidebarCollapser,
        expander: props.sidebarExpander
      }));
    }, jCore.Component);
  
    ContentHeader.prototype.sidebarToggleButtonElement = function() {
      return dom.child(this.element(), 0);
    };
  
    ContentHeader.prototype.redraw = function() {
      this.sidebarToggleButton().redraw();
    };
  
    if (typeof module !== 'undefined' && module.exports)
      module.exports = ContentHeader;
    else
      app.ContentHeader = ContentHeader;
  })(this.app || (this.app = {}));
  
new_contents: (function(app) {
    'use strict';
  
    var jCore = require('jcore');
    var helper = app.helper || require('../helper.js');
    var dom = app.dom || require('../dom.js');
  
    var SidebarToggleButton = helper.inherits(function(props) {
      SidebarToggleButton.super_.call(this);
  
      this.type = this.prop(SidebarToggleButton.TYPE_COLLAPSE);
      this.disabled = this.prop(false);
      this.element = this.prop(props.element);
      this.cache = this.prop({});
  
      this.collapser = props.collapser;
      this.expander = props.expander;
    }, jCore.Component);
  
    SidebarToggleButton.prototype.redraw = function() {
      this.redrawType();
      this.redrawDisabled();
    };
  
    SidebarToggleButton.prototype.redrawType = function() {
      var type = this.type();
      var cache = this.cache();
  
      if (type === cache.type)
        return;
  
      dom.data(this.element(), 'type', type);
      cache.type = type;
    };
  
    SidebarToggleButton.prototype.redrawDisabled = function() {
      var disabled = this.disabled();
      var cache = this.cache();
  
      if (disabled === cache.disabled)
        return;
  
      dom.disabled(this.element(), disabled);
      cache.disabled = disabled;
    };
  
    SidebarToggleButton.TYPE_COLLAPSE = 'collapse';
    SidebarToggleButton.TYPE_EXPAND = 'expand';
  
    var ContentHeader = helper.inherits(function(props) {
      ContentHeader.super_.call(this);
  
      this.element = this.prop(props.element);
  
      this.sidebarToggleButton = this.prop(new SidebarToggleButton({
        element: this.sidebarToggleButtonElement(),
        collapser: props.sidebarCollapser,
        expander: props.sidebarExpander
      }));
    }, jCore.Component);
  
    ContentHeader.prototype.sidebarToggleButtonElement = function() {
      return dom.child(this.element(), 0);
    };
  
    ContentHeader.prototype.redraw = function() {
      this.sidebarToggleButton().redraw();
    };
  
    if (typeof module !== 'undefined' && module.exports)
      module.exports = ContentHeader;
    else
      app.ContentHeader = ContentHeader;
  })(this.app || (this.app = {}));
  
subject: Refactor code for updating sidebar-toggle-button