defaultFilterFn = function (sValue, oItem, bFilterAdditionalText) {
		if (!oItem) {
			return false;
		}

		if (oItem.isA("sap.ui.core.ListItem") && bFilterAdditionalText && wordStartsWithValue(oItem.getAdditionalText(), sValue)) {
			return true;
		}

		return wordStartsWithValue(oItem.getText(), sValue);
	}
The default filter function for one and two-value. It checks whether the item text begins with the typed value.

@param {string} sValue the current filter string.
@param {sap.ui.core.Item} oItem the filtered list item.
@param {boolean} bFilterAdditionalText true, if the item should be filtered by additional text
@returns {boolean} true for items that start with the parameter sValue, false for non matching items.