src/sap.ui.core/src/jquery.sap.history.js
function getAppendId(sHash){
			var iIndex = jQuery.inArray(currentHash, hashHistory),
				i, sHistory;
			if (iIndex > -1) {
				for (i = 0 ; i < iIndex + 1 ; i++) {
					sHistory = hashHistory[i];
					if (sHistory.slice(0, sHistory.length - 2) === sHash) {
						return uid();
					}
				}
			}

			return "";
		}
function getAppendId(sHash){
			var iIndex = jQuery.inArray(currentHash, hashHistory),
				i, sHistory;
			if (iIndex > -1) {
				for (i = 0 ; i < iIndex + 1 ; i++) {
					sHistory = hashHistory[i];
					if (sHistory.slice(0, sHistory.length - 2) === sHash) {
						return uid();
					}
				}
			}

			return "";
		}
function getAppendId ( sHash ) { var iIndex = jQuery . inArray ( currentHash , hashHistory ) , i , sHistory ; if ( iIndex > - 1 ) { for ( i = 0 ; i < iIndex + 1 ; i ++ ) { sHistory = hashHistory [ i ] ; if ( sHistory . slice ( 0 , sHistory . length - 2 ) === sHash ) { return uid ( ) ; } } } return "" ; }
This function checks if the combination of the identifier and data is unique in the current history stack.
If yes, it returns an empty string. Otherwise it returns a unique id.

@private
This function checks if the combination of the identifier and data is unique in the current history stack . If yes it returns an empty string . Otherwise it returns a unique id .