How To Display Placeholders In Angularjs For Undefined Expression Values

When working with AngularJS, you might come across situations where you need to display a placeholder value when an expression evaluates to undefined. This is a common scenario when you are waiting for data to load or when a value is not available yet. Luckily, AngularJS provides a simple solution to handle this using the ngIf directive.

The ngIf directive allows you to conditionally render HTML elements based on an expression's truthiness. In this case, we can use it to check if our expression is undefined and display a placeholder instead. Let's walk through the steps to achieve this functionality in your AngularJS application:

First, you need to include the AngularJS library in your project if you haven't already done so. You can either download the library and include it in your project or use a CDN link to access it. Make sure to include AngularJS script tag in your HTML file.

Next, in your AngularJS controller or component, define a variable that might evaluate to undefined at some point. For example, let's say we have a property called `name` that is initially undefined.

Then, in your HTML template, you can use the ngIf directive to check if the `name` property is undefined. If it is, you can display a placeholder message like "Name not available" using the ngIf directive.

Here's a simple example to demonstrate this concept:

<title>Display Placeholders in AngularJS</title>
    


    <div>Name not available</div>
    <div>{{ ctrl.name }}</div>


    angular.module("myApp", [])
    .controller("MyController", function() {
        this.name = undefined;
    });

In this example, we have defined a controller called `MyController` with a property `name` set to undefined. We then use two `