AngularJS has become one of the most popular JavaScript frameworks for building dynamic and interactive web applications. With its powerful features and easy-to-use syntax, it has gained a large following among developers. One of the key components of AngularJS is its ability to create custom directives, which allow developers to extend HTML with new elements and attributes. In this article, we will take a deep dive into one such directive – angular-slider.
Angular-Slider: An Overview
Angular-slider is a slider directive implementation for AngularJS that does not require any jQuery dependencies. It is designed to work with AngularJS version 1.1.4 or higher and also supports optional isolate scope bindings. This means that you can use this directive in your AngularJS projects without worrying about any external dependencies.
The main purpose of angular-slider is to provide an easy way to add sliders to your web applications. Sliders are commonly used in web design to allow users to select a value from a range of options. For example, you may have seen sliders on e-commerce websites where users can select a price range to filter products. With angular-slider, you can easily add such functionality to your own projects.
Example:
To get started with angular-slider, you first need to include the necessary files in your project. You can either download the source code from GitHub or install it using Bower or NPM. Once you have included the files, you can use the angular-slider directive in your HTML code as follows:
<slider ng-model="value" min="0" max="100"></slider>In the above code, we have specified the ng-model attribute to bind the slider’s value to a variable called value. We have also set the minimum and maximum values for the slider using the min and max attributes respectively. By default, the slider will have a horizontal orientation, but you can change it to vertical by adding the vertical attribute.
Range
One of the most useful features of angular-slider is its ability to define a range of values. This means that instead of selecting a single value, users can select a range of values using two handles. To enable this feature, you simply need to add the range attribute to your slider element as shown below:
<slider ng-model="range" min="0" max="100" range></slider>In the above code, we have specified the ng-model attribute to bind the selected range to a variable called range. Now, when you move the handles, the range variable will be updated with an array containing the minimum and maximum values of the selected range.
Formatting
Another useful feature of angular-slider is its ability to format the slider’s value in different ways. By default, the slider displays the selected value as a number, but you can change this by using the translate attribute. This attribute allows you to specify a function that will be used to format the slider’s value. For example, if you want to display the value with a currency symbol, you can do so as follows:
<slider ng-model="value" min="0" max="100" translate="formatCurrency"></slider>In your controller, you can define the formatCurrency function as follows:
$scope.formatCurrency = function(value) {
return '$' + value;
}And in your HTML, the slider’s value will now be displayed with a dollar sign in front of it. You can use this feature to format the value in any way you want, such as adding commas or decimals.
Known Issues
While angular-slider is a great tool for adding sliders to your AngularJS projects, there are a few known issues that you should be aware of. One of the most common issues is when using the slider inside an ng-repeat directive. In such cases, if you apply filters or orders to the repeated elements, the slider can abruptly change its position. This happens because the value attached to the slider causes a filter to activate or the order to change.
Example:
Let’s say we have a list of items with their corresponding costs, and we want to display them in ascending order based on their cost. We can do so by using the orderBy filter as follows:
<div ng-repeat="item in items | orderBy:'cost'">
<slider ng-model="item.cost" min="0" max="100"></slider>
</div>In the above snippet, the slider’s position will change whenever the orderBy filter is applied, which can be a jarring experience for the user. To avoid this issue, it is recommended to use the track by expression in your ng-repeat directive, which will ensure that the slider maintains its position even when the order changes.
Roadmap
The developers behind angular-slider are constantly working to improve the directive and add new features. Some of the upcoming features on their roadmap include support for touch events, custom styling options, and more. They also welcome contributions from the community, so if you have any ideas or suggestions, feel free to submit a pull request on GitHub.
License: MIT
Angular-slider is released under the MIT license, which means that you can use it for both personal and commercial projects without any restrictions. You can also modify the source code and distribute it as long as you include the original copyright notice and license.
Conclusion
In conclusion, angular-slider is a powerful and easy-to-use directive for adding sliders to your AngularJS projects. It offers a range of useful features such as range selection, value formatting, and more. While there are a few known issues, the developers are actively working to improve the directive and add new features. So if you’re looking to add sliders to your web applications, be sure to give angular-slider a try.