Converts Array of Objects to HashMap

ArrayToHashMap

    function isFunction(func){
        return Object.prototype.toString.call(func) === '[object Function]';
    }
    
    /**
     * This function converts an array to hash map
     * @param {String | function} key describes the key to be evaluated in each object to use as key for hasmap
     * @returns Object
     * @Example 
     *      [{id:123, name:'naveen'}, {id:345, name:"kumar"}].toHashMap("id")
            Returns :- Object {123: Object, 345: Object}
            
            [{id:123, name:'naveen'}, {id:345, name:"kumar"}].toHashMap(function(obj){return obj.id+1})
            Returns :- Object {124: Object, 346: Object}
     */
    Array.prototype.toHashMap = function(key){
        var _hashMap = {}, getKey = isFunction(key)?key: function(_obj){return _obj[key];};
        this.forEach(function (obj){
            _hashMap[getKey(obj)] = obj;
        });
        return _hashMap;
    };