currency directive to prepend a $ signto the value and add . every three digits. The model value stays without these ornaments.

Currency formatter angular.js directive

module.directive('currency', function () {
    return {
        require: 'ngModel',
        link: function(elem, $scope, attrs, ngModel){


            $scope.addPoints = function(val){
                console.log("formater points", val);
				var count = 0, result;
				return _.reduceRight(val, function(memo, item){
					if(count % 3 === 0 && count > 0){
                        result = item + "." + memo
					}
					else{
						result = item + memo;
					}
					count++;
                    console.log(result);
                    return result;
				},"")
            };


            $scope.addDollarSign = function(val){
                console.log("formater dollar", val);
                return '$' + val;
            };

            /*
                Formatters are called when the ngModel value is changed from inside the code, not through UI interaction.
            */
            ngModel.$formatters.push($scope.addPoints);
            ngModel.$formatters.push($scope.addDollarSign);

            /*
            Parsers are called to extract the actual ngModel value from the inmput of the user.
            */
			//Remove format points
            ngModel.$parsers.push(function(val){
                return val.replace(/\./g, '');
            });

			//Remove dollar sign
            ngModel.$parsers.push(function(val){
                return val.replace(/^\$/, '');
            });

            ngModel.$viewChangeListeners.push(function(){
                //use the formatters with the modelValue
                ngModel.$setViewValue($scope.addDollarSign($scope.addPoints(ngModel.$modelValue)), 'format currency');
                //render the value in the ui 
                ngModel.$render();
            })
        }
    }
})