custom directive angularjs for replace input with only numbers

customValidation.js

(function() {
    angular.module("BauVoiceApp").directive("customValidation", function() {
        return {
            require: "ngModel",
            link: function(scope, element, attrs, modelCtrl) {
                modelCtrl.$parsers.push(function(inputValue) {
                    const numberPattern = /\d+/g;
                    let transformedInput = inputValue.match(numberPattern)[0];
                    if (transformedInput != inputValue) {
                        modelCtrl.$setViewValue(transformedInput);
                        modelCtrl.$render();
                    }

                    return transformedInput;
                });
            },
        };
    });
})();