The use case is to convert an array of objects into a hash map based on string or function provided to evaluate and use as the key in the hash map and val
Using simple Javascript
var createMapFromList = function(objectList, property) { var objMap = {}; objectList.forEach(function(obj) { objMap[obj[property]] = obj; }); return objMap; }; // objectList - the array ; property - property as the key