How to stop empty numbers in angular.js

My goal is to ensure that an input with a required attribute always has some value, and if left empty, defaults to zero.

<input ng-model='someModel' required>

I have created the following directive:

App.directive('input', function () {
    return {
        scope: {},
        link: function ($scope, $element, $attrs) {
            if ($attrs.type == 'number') {
                if ($element[0].required) {
                    $element.on('blur', function(){
                        if(this.value===''){
                            this.value=0;
                        }
                    });
                }
            }
        }
    };
});   

I am aware that using this. value directly may not be the best practice as it changes the value and not the scope. However, I am unsure of how to change the scope itself.
Using $scope.value does not seem to work in this scenario.
I aim for this directive to be as generic as possible without needing to specify the model name in the scope.

Answer №1

Here is an alternative method.

App.directive('input', function () {
    return {
        require: 'ngModel',
        link: function (scope, element, attrs) {
            if (attrs.type === 'number' && attrs.required) {

                function checkAndUpdate() {
                  if (!scope[attrs.ngModel]) {
                    scope.$apply(function() {
                      scope[attrs.ngModel] = 0;
                    });
                  }
                }

                element.on('blur', checkAndUpdate)

                // remove listener when scope is no longer in use
                scope.$on('$destroy', function() {
                  element.off('blur', checkAndUpdate)
                })

            }
        }
    };
});

http://plnkr.co/edit/4yDTNUfdpu2ql1EmTZ3B?p=preview

Answer №2

In my opinion, using isNaN(parseInt('')) is a clearer choice compared to using the exact equals method. Both options will work effectively, but the former directly indicates that you are checking for an empty entry.

While this solution may seem a bit messy, it does show progress in the right direction. Perhaps someone with more experience could refine it further.

App.directive('input', function () {
    return {
        scope: {},
        link: function ($scope, $element, $attrs, ngModel) {
            if ($attrs.type == 'number') {
                if ($element[0].required) {
                    $element.on('blur', function(){
                        if(isNaN(parseInt(ngModel.$viewValue))){
                            scope.$apply(function(){
                              ngModel.$viewValue = 0;
                            }
                        }
                    });
                }
            }
        }
    };
});   

Answer №3

Using AngualarJS:

var replaceWithZeros = (function(angular) {
  "use strict";
  var example = angular.module('example', []);
  example.controller('exampleCtrl', function($scope) {
    $scope.someModel = '0.00';
    $scope.someFunction = function(curVal) {
      if (!curVal) {
        $scope.someModel = '0.00';
      }
    };
  });
})(window.angular);

The HTML:

<main ng-app="example" ng-controller="exampleCtrl">  
  <input ng-model="someModel" ng-blur="someFunction(someModel)" required="required"/>
</main>

Check out the demo to see everything in action. The code is displayed in HTML here, but it's presented in Jade in the live demo.

http://codepen.io/nicholasabrams/pen/xGPvJd

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Error in Typescript: Function not being triggered on button click

As someone who is just starting out with typescript, I've been tackling a simple code that should display an alert message in the browser when a button is clicked. I've experimented with the button and input tags, as well as using both onclick ev ...

Effectively detect the 'scrollend' event on mobile devices

When implementing the -webkit-overflow-scrolling: touch; style on a mobile element, dealing with scroll events can be quite challenging as they are triggered by various actions such as 'flicking', 'panning' and when the scroll comes to ...

What exactly is the concept of lazily installing a dependency?

The website here contains information about the changes in Ember 2.11. Ember 2.11 now utilizes the ember-source module instead of the ember Bower package. In the upcoming Ember CLI 2.12 release, Bower will no longer be installed by default but will only ...

I am looking to amalgamate a pair of scripts into a single cohesive work

Currently, I am utilizing jQuery toggleClass to switch CSS styles. $ (".test").click(function () { $(this).toggleClass('active'); }); Whenever I click outside of the Bootstrap menu, the menu gets hidden. In addition to this functio ...

Setting up a textarea tooltip using highlighter.js

I'm experimenting with using highlighter.js within a textarea. I've customized their sample by substituting the p with a textarea enclosed in a pre tag (for right-to-left language settings). <div class="article" style="width: 80%; height: 80% ...

What is the best way to change an object into a string in node.js?

Recently, I've delved into the world of node js and I'm eager to create a basic coap client and server using this technology. Successfully, I managed to set up a server hosting a text file, but now I aim to access it from the client. var coap = ...

The function Router.use is looking for a middleware function, but instead received an object in node.js /

I encountered an issue while trying to setup routing in my application. Whenever I attempt to initialize a route using app.use() from my routes directory, I receive an error stating that Router.use() requires a middleware function but received an Object in ...

The step-by-step guide to automate clicking on an angular dropdown menu using Selenium

Having some trouble using python selenium to automate report generation on a website. The javascript is making it difficult for me to identify the element I need to click on the page. When inspecting the element in Firefox, there is a DOM Event icon that c ...

An error message stating "ReferenceError: str is not defined" was encountered in Firefox while using the Gettext Library

The gettext.js library seems to be giving me trouble. When I try to run the "index.html" file, an error message saying "ReferenceError: str is not defined" pops up. this.LCmessages[lang] = new jsGettext.Parse(str); I'm not sure where the str variabl ...

Discovering a website's console content using the "web-request" npm package

I recently added the web-request NPM package to my project with the goal of retrieving console messages from a specific website. However, I encountered an issue as I was unsure of how to achieve this. var result = await WebRequest.get('http://disco ...

What is the reason that TypeScript does not automatically infer void & {} as the never type?

When TypeScript's void type is used in combination with other types through intersection, the outcomes vary. type A = void & {} // A becomes void & {} type B = void & '1' // B becomes never type C = void & 1 // C becomes never type D = void ...

A method of binding data from an array of objects in Vue using v-bind

I am tasked with rendering a board that is 20x15 and placing creatures on it. The information on where to place the creatures is stored in this.creaturesOnBoard within the gameEngine. My plan is to take X and y coordinates, then check if a creature exists ...

Warning: Attempting to destructure the property 'name' from 'req.body', which is undefined, is causing a TypeError

Currently, I am diving into the world of MERN Stack web development and running into a unique issue. When using Postmate to input data from the body to the database, everything works smoothly when done from the server.js file. However, when attempting the ...

Using jQuery ajax links may either be effective or ineffective, depending on the scenario. At times

Can someone please assist me in understanding why an ajax link may or may not work when clicked? It seems to function intermittently. window.onload = function(){ function getXmlHttp(){ ...... // simply ajax } var contentContainer = ...

Unable to use NodeJS await/async within an object

I'm currently developing a validation module using nodeJs and I'm facing difficulties understanding why the async/await feature is not functioning correctly in my current module. Within this module, I need to have multiple exports for validation ...

Issue: The initial parameter should be a File or Blob object

Hey there! I'm currently utilizing the compressorjs plugin for compressing images, but I'm encountering an issue when selecting images. You can find out more about the plugin here. Here is my code snippet: window.resolveLocalFileSystemURL( ...

Using Google Chart API to create stacked bar charts with annotations using symbols

I am trying to annotate the bars in my stacked bar chart with currency symbols for profit and costs. While I have been able to successfully annotate the bars without currency symbols, I am facing difficulties in displaying them with the $ prefix. Can anyo ...

cors library returns success messages, not errors

Currently, I am working on implementing the cors package within a node and express environment to validate whether the requesting domain can access my resources. Setting up the validation part following the official documentation was not an issue. However, ...

Having difficulty controlling the DOM within an AngularJS template

My website utilizes AngularJS templates, specifically a Single Page Application (SPA). Within one of the templates, I am utilizing a tab control from the AngularUI library named Ui-Tabset. During the rendering process, this control generates a ul element ...

Retrieve the numerical key within an md-directive

How can I access a Json object with a numerical key in an ng directive? Take a look at the object below: { 0 : { value : { firstname : "John" , lastname : "Doe" } } I want to retrieve the first name of this object using a md directive like: <th md-c ...