Using local storage to maintain navigation collapse state.

localstore_nav_controller.js

angular.module("app.controllers")
.controller("NavCtrl", [
  "$scope",
  "$window",
  function($scope, $window) {

    $scope.toggleCollapse = function() {
      $scope.collapsed = !$scope.collapsed;
      setCollapsed($scope.collapsed);
    };

    var store = $window.localStorage;
    var key = 'header-collapsed';

    function init() {
      if( store.getItem(key) ) {
        $scope.collapsed = true;
      } else {
        $scope.collapsed = false;
      }
    }

    function setCollapsed(setting) {
      if (setting) {
        store.setItem(key, setting);
      } else {
        store.removeItem(key);
      }
    }

    // Initialize
    init();

  }
]);