dist/amd.riotx+riot.js
function getItemId(keyAttr, originalItem, keyedItem, hasKeyAttrExpr) {
      if (keyAttr) {
        return hasKeyAttrExpr ?  tmpl(keyAttr, keyedItem) :  originalItem[keyAttr]
      }

      return originalItem
    }
function getItemId(keyAttr, originalItem, keyedItem, hasKeyAttrExpr) {
      if (keyAttr) {
        return hasKeyAttrExpr ?  tmpl(keyAttr, keyedItem) :  originalItem[keyAttr]
      }

      return originalItem
    }
function getItemId ( keyAttr , originalItem , keyedItem , hasKeyAttrExpr ) { if ( keyAttr ) { return hasKeyAttrExpr ? tmpl ( keyAttr , keyedItem ) : originalItem [ keyAttr ] } return originalItem }
Return the value we want to use to lookup the postion of our items in the collection
@param   { String }  keyAttr         - lookup string or expression
@param   { * }       originalItem    - original item from the collection
@param   { Object }  keyedItem       - object created by riot via { item, i in collection }
@param   { Boolean } hasKeyAttrExpr  - flag to check whether the key is an expression
@returns { * } value that we will use to figure out the item position via collection.indexOf
Return the value we want to use to lookup the postion of our items in the collection