AngularJS: ngModel $parsers.

HTML

<div ng-app="myApp" ng-controller="MainCtrl">
   
    <input test="" type="text" ng-model="model"/>{{model}}
</div>

JavaScript

var app = angular.module('myApp', []);

app.controller('MainCtrl', function($scope) {
   
});



app.directive('test', function() {
    return {
        require: '^ngModel',
        link: function(scope, element, attrs, ngModel) {
            ngModel.$parsers.push(function(value) {
             ngModel.$viewValue="123";
             ngModel.$render();
                return value.replace(/\D/g, '');
            });
            
        }
    };
});