Directive to handle number field scenarios on input[type=text]

numbers.directive.js

(function() {
  'use strict';

  angular
    .module('starter.services')

  /**
   * @ngdoc directive
   * @name app.directive:numbersOnly
   * @restrict 'A'
   * @element ANY
   * @description
   * directive to only allows numbers
  */
    .directive('numbersOnly', function ($window) {
      return {
        require: 'ngModel',
        link: function (scope, element, attr, ngModelCtrl) {
            function fromUser(text) {
                if (text) {
                    var allowDecimal = attr.allowDecimals;
                    var setDecimalPlaces = attr.setDecimalPlaces || 2;
                    var maxNumber = attr.maxNumber ? parseInt(attr.maxNumber) : undefined;
                    var transformedInput = text.replace(/[^0-9.]/g, '');
                    if(transformedInput){
                        var lst = transformedInput.split('.');
                        var isDecimal;
                        var number, numberDigits;
                        var decimal, decimalDigits;

                        if(lst.length === 2){
                            isDecimal = true;
                            number = lst[0]
                            numberDigits = number.length;
                            decimal = lst[1];
                            decimalDigits = decimal.length;
                        }else if(lst.length === 1){
                            isDecimal = false;
                            number = lst[0]
                            numberDigits = number.length;
                        }

                        if(maxNumber && numberDigits > maxNumber){
                            if(isDecimal){
                                transformedInput = number.substring(0, maxNumber) + '.' + decimal;
                            }else{
                                transformedInput = number.substring(0, maxNumber);
                            }
                        }

                        if(allowDecimal && isDecimal){
                            if(decimalDigits > setDecimalPlaces){
                                transformedInput = (parseFloat(transformedInput).toFixed(setDecimalPlaces)).toString();
                            }
                        }else{
                            transformedInput = parseInt(transformedInput).toString();
                        }
                    }
                    
                    if (transformedInput !== text) {
                        ngModelCtrl.$setViewValue(transformedInput);
                        ngModelCtrl.$render();
                    }

                    return transformedInput;
                }
                return undefined;
            }            
            ngModelCtrl.$parsers.push(fromUser);
        }
      };
    });
})();

Usage.html

<!-- Use attributes to configure input accordingly -->
<input type="text" placeholder="Enter number" numbers-only max-number="10" allow-decimals="true" set-decimal-places="3"/>