old_contents: 
  window.infrastructure = window.infrastructure || {};
  
  window.infrastructure.storage = (function (Promise, localStorage) {
      'use strict';
  
      var exports = {};
  
      exports.get = function (key, defaultValue) {
  
          var value = localStorage[key];
  
          if (value == null) {
              return Promise.resolve(defaultValue);
          }
  
          return Promise.resolve(JSON.parse(value));
      };
  
      exports.set = function (key, value) {
  
          localStorage[key] = JSON.strigify(value);
  
          return Promise.resolve(true);
  
      };
  
      return exports;
  
  }(window.Promise, window.localStorage));
  
new_contents: 
  window.infrastructure = window.infrastructure || {};
  
  window.infrastructure.storage = (function (Promise, localStorage) {
      'use strict';
  
      var exports = {};
  
      exports.get = function (key, defaultValue) {
  
          var value = localStorage[key];
  
          if (value == null) {
              return Promise.resolve(defaultValue);
          }
  
          return Promise.resolve(JSON.parse(value));
      };
  
      exports.set = function (key, value) {
  
          localStorage[key] = JSON.stringify(value);
  
          return Promise.resolve(true);
  
      };
  
      return exports;
  
  }(window.Promise, window.localStorage));
  
subject: Fix typo