code: function getOrFakeBackend( browser, webStorageName ) {
     const browserConsole = browser.console();
     const store = window[ webStorageName ];
     if( store.setItem && store.getItem && store.removeItem ) {
        try {
           const testKey = 'ax_.storage.test';
           // In iOS Safari Private Browsing, this will fail:
           store.setItem( testKey, 1 );
           store.removeItem( testKey );
           return store;
        }
        catch( e ) {
           // setItem failed: must use fake storage
        }
     }
  
     if( browserConsole ) {
        const method = 'warn' in browserConsole ? 'warn' : 'log';
        browserConsole[ method ](
           `window.${webStorageName} not available: Using non-persistent polyfill. \n` +
           'Try disabling private browsing or enabling cookies.'
        );
     }
  
     const backend = {};
     return {
        getItem( key ) {
           return backend[ key ] || null;
        },
        setItem( key, val ) {
           backend[ key ] = val;
        },
        removeItem( key ) {
           if( key in backend ) {
              delete backend[ key ];
           }
        }
     };
  }
docs: ////////////////////////////////////////////////////////////////////////////////////////////////////////////