Ternary operator in AngularJS templates

Expanding conditional rendering with ng-class and ng-style

When dealing with multiple conditions or classes, make use of ng-class and ng-style. They use object notation where object keys are class names or style properties and their values are the conditions:

<!-- Turn me into a highlighter or a bold ninja based on booleans in the scope ;) -->
<span ng-class="{'highlight': isHighlighted, 'bold': isBold}">
  Select me!
</span>
<!-- I can become a blue beetle or a gray goose. Surprise me! -->
<span ng-style="{'color': isColored ? 'blue' : 'gray'}">
  Watch my color!
</span>
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The ng-class directive toggles classes based on conditions, whereas ng-style allows dynamic styling.

Directing attributes to the ternary operator

HTML attributes can make direct use of the ternary operator:

<!-- Either an author or a ghost. Spooky, right? ;) -->
<input type="text" placeholder="{{ user.isLoggedIn ? 'Type your epic novel here.' : 'Sorry, ghosts can\'t type.' }}">


It allows writing efficient templates without cluttering your controllers with excessive logic.

Complex conditionals with objects and maps

For complex conditions, you can use an object with boolean properties inside ng-class or ng-style:

<!-- Superpowers activated based on scope booleans -->
<div ng-class="{ 'active': isActive, 'disabled': !isAvailable }">Action</div>


This enhances the readability and maintainability of your code.

Crafting bespoke filters for advanced rendering

You can design custom filters to manage intricate conditional rendering within the template:

<p>{{ username | conditionalFormatter:'Hello,':'Guest' }}</p>
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Here, the conditionalFormatter filter is applying a custom condition to username.

Compatibility considerations with different AngularJS versions

AngularJS support for ternary operation varies by version. For versions 1.1.5 and above, ternary operations are directly supported. Earlier versions might require alternative methods like condition && true-part || false-part syntax.

Optimize AngularJS templates with ternary operators

Ensure your templates maintain a focus on view logic. Complex business logic can make templates hard to maintain. Balance power with simplicity.

Streamline controllers using inline ternary syntax

Inline ternary syntax can avoid unnecessary controller functions and logic. This results in leaner controllers and templates that are simpler to read and test.

Understand parsing with the $parse service

In AngularJS, the $parse function supports ternary operations:

// Inception: A condition within a condition. Mind blown, right? ;)
$scope.$eval("condition ? 'returnValueIfTrue' : 'returnValueIfFalse'");
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It lets you evaluate expressions from strings, including those with ternary operators.