AngularJs directive: Restrict user to enter value with only ‘N’ decimal places

Directive Name: aDecimals
How to Use: Add the attribute: n-decimals=”n” where n is the number like 2,3…
If you want to restrict user to 2 decimal points, write like this: evo-decimals=”2″

Source Code:

The following code will restrict user to enter numeric value with decimal upto 4 place.

Javascript code

var app = angular.module('plunker', []);
 
app.controller('MainCtrl', function($scope) {
 
});
 
  app.directive('nDecimals', [nDecimals]);
    function nDecimals() {
        return {
            restrict: 'A',
            link: function (scope, element, attr) {
                element.on('input', function (e) {
                  // Read the attribute to know the 'N' number places
                    var maxDecimal = Number(element.attr('n-Decimals'));
                    //Read the enetered value
                    var sal = element.val();
                    var parts;
                    if (sal.indexOf(".") !== -1) {
                        parts = sal.split(".");
                        if (parts[1].length > maxDecimal) {
                            element.val(sal.substr(0, sal.length - 1));
                        }
                    }
                });
                // destroy event.
                scope.$on('$destroy', function () {
                    element.off('input');
                });
            }
        };
    }

HTML code

 <input type="number" n-decimals="4" ng-model="salary"/>

In the above directive we are using the ‘input’ event which is very similar to the ‘onchange’ event. The ‘input event is fired synchronously when the value of an ‘input’ or ‘textarea’ element is changed while ‘onchange’ occurs when the element loses focus, after the content has been change.

Author: Hirendra Sisodiya

Programmer at PSPL. Can be found on Google Plus.