Money formatting directive in Angular

Question

I need a directive for filtering a field for currency, so a user just needs to type and the decimal is implied.

Needs:

1. Format decimal field as user typ

Answer 1

.:: Updated Answer - July 14 ::.

---

Check this simple directive:

app.directive('price', [function () {
    return {
        require: 'ngModel',
        link: function (scope, element, attrs, ngModel) {
            attrs.$set('ngTrim', "false");

            var formatter = function(str, isNum) {
                str = String( Number(str || 0) / (isNum?1:100) );
                str = (str=='0'?'0.0':str).split('.');
                str[1] = str[1] || '0';
                return str[0].replace(/(\d)(?=(\d\d\d)+(?!\d))/g, '$1,') + '.' + (str[1].length==1?str[1]+'0':str[1]);
            }
            var updateView = function(val) {
                scope.$applyAsync(function () {
                    ngModel.$setViewValue(val || '');
                    ngModel.$render();
                });
            }
            var parseNumber = function(val) {
                var modelString = formatter(ngModel.$modelValue, true);
                var sign = {
                    pos: /[+]/.test(val),
                    neg: /[-]/.test(val)
                }
                sign.has = sign.pos || sign.neg;
                sign.both = sign.pos && sign.neg;

                if (!val || sign.has && val.length==1 || ngModel.$modelValue && Number(val)===0) {
                    var newVal = (!val || ngModel.$modelValue && Number()===0?'':val);
                    if (ngModel.$modelValue !== newVal)
                        updateView(newVal);

                    return '';
                }
                else {
                    var valString = String(val || '');
                    var newSign = (sign.both && ngModel.$modelValue>=0 || !sign.both && sign.neg?'-':'');
                    var newVal = valString.replace(/[^0-9]/g,'');
                    var viewVal = newSign + formatter(angular.copy(newVal));

                    if (modelString !== valString)
                        updateView(viewVal);

                    return (Number(newSign + newVal) / 100) || 0;
                }
            }
            var formatNumber = function(val) {
                if (val) {
                    var str = String(val).split('.');
                    str[1] = str[1] || '0';
                    val = str[0] + '.' + (str[1].length==1?str[1]+'0':str[1]);
                }
                return parseNumber(val);
            }

            ngModel.$parsers.push(parseNumber);
            ngModel.$formatters.push(formatNumber);
        }
    };
}]);

And use it like this:

See it live in this PLUNKER (July 14)