Introduction to AngularJS Services
Angular is a framework that is written in JavaScript which is used to design the frontend. This framework is very powerful, which is used to make single-page applications. By using the angular framework we can write our application which follows the Model-view-controller approach. In this topic, we are going to learn about AngularJS Services.
Angular also let us create services that are used to communicate to the backend server basically. Angular provides us many built-in services and lets us create our own services as well. These services are injectable which follows the dependency injection mechanism. These services are JavaScript functions which perform some specific task. we have some examples for angular built-in services like $location, $route, $window and many more. But angular js application will only instantiate the service if and only if the component depends on it or have to perform some task using that service. Basically each component depends upon some service.
Explain AngularJS Services
We have so many built-in services provided by angular js and we can also create our custom. Some of the built-in services are listed below :
1. $parse: This service is used to convert any angular expression into the appropriate functions.
2. $rootScope: In angular js, it is used to provide root scope to a variable or we can say it provides global scope to the variable. It provides the separation between the model and view. Every angular application has a single root scope.
3. $rootElement: This service is we can say that the root element of the angular application.
4. $locale: This in-built angular service provides us the localization rule for various components of angular js.
5. $q: This service is used to run us any function asynchronously. This service uses the return value which can be anything when they are done with the processing.
6. $sceDelegate: This service is used by another service which named as $sce in the backend.
7. $log: This angular js built-in service is very useful. Basically used for console logger purpose to track the loges.
8. $location: Basically this service parses the URL from the browser and makes this URL available for our angular js application. Changes that it made to the URL reflected the $location service.
9. $httpBackend: This angular js service is used for browser incompatibilities.
10. $filter: Filter is used to filtering the elements. In other words filter in angular js is used to filter the element and object and returned the filtered items. Basically filter selects a subset from the array from the original array.
Syntax :
{{ arrayexpression | filter : expression : comparator : anyPropertyKey }}- comparator: We use a comparator to compare any value. Comparator basically compares the actual and expected values from filtered and object array respectively. This works similar to the comparator in java.
- anyPropertyKey: anyPropertyKey is used to compare the value corresponding to the giver key. It has a default value as $.
- arrayexpression: It takes the array on which we applied the filter.
- expression: It is used to select the items from the array after the filter conditions are met.
11. $document: This service is used to read the jQuery wrapped reference.
12. $http: This service provides communication between browser and http servers. it can connect to Http server through browser’s XML request object or by the use of json object.
13. $httpParamSerializer: This service is used to convert the object to string and it is a default param serializer.
14. $interval: This service is an angular wrapper.
15. $xhrFactory: This angular js service is used to create XMLHttpRequest objects.
16. $exceptionHandler: Whenever we got an uncaught exception in our angular application then that exception transfer to this service. It has deflated implementation which simply transfers this to $log.error which is used to print out an exception to browser console for further use.
17. $interpolate: This service is used by the compiler for data binding it is basically a service used for data binding. It complies with a string for interpolation.
18. $httpParamSerializerJQLike: It is a $http param serializer, this serializer sort the params alphabetically. It also uses jQuery’s method of logic.
19. $controller: This is the main point from where the application gets the start. This is also responsible for instantiating angular components. So basically it instantiating angular controller.
example:
$controller(constructor, locals);If we call this from string then it will consider as a string which is used to retrieve the constructor following thing :
- check the string on the current scope.
- check the controller with the given name registered.
and if this called from function then it considered as a constructor function.
20. $templateCache: If we load any template for the first time then it is loaded into the template cache for faster retrieval.
21. $window: This service is used to refer to the browser window object. As it is a global variable so it causes a testing problem because it is globally present in JavaScript. So in angular, we always refer this $window service to avoid this type of problem.
22. $templateRequest: This service is used to run the security checks. After successfully running the security checks it downloads the template using $http and on the success, it stores the templet content into the $templateCache.
23. $animateCss: This service is used to perform the animations. But for this, we need to include ngAnimate to have animations.
24. $compile: This service is used to compile the DOM or HTML element into a template and produces a template function. Which we further use to link template and scope together.
25. $cacheFactory: This service is used to create the cache object. This service contains, retrieves the key-value pair and hold them and provides access to other services.
26. $timeout: It is an angular wrapper service for the timeout.
27. $anchorScroll: This service is used to scroll to the page which is specified in $location.hash().
28. $sce: This service issued to provide contextual escaping.
29. $animate: This service is used to provide exposure to DOM utility methods which in turn provide the support for animations.
Conclusion
So angular services are used to filter our data, communication between server and browser, parsing and many more. We can also have our own services which perform their own logic according to the requirement.
Recommended Articles
This is a guide to AngularJS Services. Here we discuss a brief overview and built-in services provided by angular js respectively. You may also have a look at the following articles to learn more –
