AngularJS is an open-source JavaScript framework developed and maintained by Google. It provides numerous useful tools for creating and managing front-end web applications. AngularJS is the most widely used web-app framework, and its popularity is rising after the introduction of the latest version, i.e., AngularJS 4.0. Despite that, the Angular experts struggle with different issues based on AngularJS performance. However, it has many options of its own to optimize AngularJS performance.
AngularJS development has been used to build many renowned and heavy traffic websites such as Gmail, Google, Paypal, Netflix, Virgin America, and many more. It is based on the MVC model (Model View Controller) and is a great framework to develop Single Page Web apps.
AngularJS can handle DOM and AJAX on its own instead of coding them and is the major benefit of using this framework. It also provides various tools for developers to deliver modular building blocks by mix match and test code. The developers can also add an HTML page just by using a few simple tags.
Though Angular provides superfast performance by default, while designing complex and realistic applications, it shows some problems and affects the performance of your application. The reason for such a suspicious performance can arise by not following best practices by the team of developers.
As a result, it requires to optimize AngularJS applications that can tackle the threat over its performance. So, now we will learn some tips to optimize AngularJS performance to get the best performing application. But before that, let’s know more about AngularJS development.
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What is AngularJS?
AngularJS is a structured, open-source JavaScript framework used for building dynamic single-page applications. It is a web framework that uses code templates written in HTML to carry-out a particular command or function. It was developed in 2009 by ‘Misko Hevery’ at Brat Tech LLC. Now, it is maintained by Google.
AngularJS has data binding and dependency functionality, which saves time from writing lengthy codes. All such features are packaged in a browser and make it the most suitable server technology.
There is a hands-on difference between a Static document and a Dynamic Application. Therefore, the Dynamic Application usually prefers libraries and a framework that supports the development of web apps. At the same time, the library held a number of functions that are used to perform specific operations. These frameworks automatically fetch the data and call the relevant function when required. AngularJS can create new HTML constructs that, in the end, eliminate this mismatch effectively. Hence, it creates new syntax with the help of these directives.
Concepts of AngularJS
AngularJS framework works on the following terminologies or concepts in web app development.
1. Modules
Modules are defined as a container that collects or holds various parts of an application. Basically, a Module is a set of functions defined in the JavaScript file. A module is very useful and works perfectly in dividing an application into small and reusable components.
2. Expressions
The Expressions in AngularJS are expressed with {{ }}, and it indicates the data binding in HTML. Such expressions are added to the HTML templates. However, the Expressions do not support control flow statements while supporting the filters.
3. Directives
Directives indicate the compiler to relate a behavior with the DOM element or modify it. AngularJS framework has several directives such as ng-if, ng-view, ng-app, ng-controller, etc.
4. Controller
The Controller is a JavaScript object constructor function. Basically, it controls the AngularJS web or mobile applications.
5. Scope
A Scope is a JavaScript object that acts as a bridge between the View and the Controller. Overall, it is the source of data in AngularJS. With the help of the Scope object, each assignment and data manipulation takes place.
6. Validations
Validation takes place with the help of AngularJS controls and forms.
7. Data Binding
Data Binding coordinates to view and model about any changes in any of these two.
8. Services
Services are the singletons that are used by controllers, directives, and other services.
9. Filters
Filters allow you to display the data formatting on DOM, and it also extends the behavior of directives and binding expressions. These filters format the values or apply them specifically.
10. Dependency Injection
Dependency Injection is a designed pattern that is used to handle dependencies of numerous components of the software. It also allows the loosely-structured architecture development.
11. Routing
The service of $routeProvider manages all the operations of Routing. It effectively divides the map into multiple views. Routing helps to split the Single Page Applications into different views.
12. Testing
The codes are getting tested, which are developed by the Dependency Injections. Whereas some of the popular testing frameworks are Jasmine and Karma, these two are the majorly used technologies among AngularJS developers.
Advantages of AngularJS
- It is quite easy to work on and learn the AngularJS With a few simple modifications, you can achieve the benefits of AngularJS in minimum time.
- AngularJS allows two-way data binding, enabling view and model to coordinate with the changes among one another.
- With AngularJS, the developers don’t have to go with observable functions. It automatically analyzes the DOM and creates the binding on the basis of Angular-specific element attributes. This saves developers time from writing lengthy codes.
- Most of the framework requires the developer to divide the application into multiple small components or MVC components and then write codes to join these components. Whereas AngularJS is capable of solving this issue easily, as it combines the components automatically.
Disadvantages of AngularJS
- The AngularJS applications are not safe. Such applications require server-side authentication, and it is necessary to maintain the security of the application.
- If the application user disables the JavaScript, then in the application, nothing gets displayed except the basic page.
- Sometimes, AngularJS becomes quite complex to handle it. As there are multiple ways to perform the same task, and it results in confusion. Hence, it requires considerable effort to manage a task.
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Tips to Optimize AngularJS Performance
There are many built-in tools to optimize AngularJS, but the performance issue still shows pores in the framework. While working with AngularJS, if you don’t have a massive infrastructure like Google, then you need to implement some preventive measures or the best practices to optimize AngularJS performance to boost the application.
Before heading towards the tips to optimize AngularJS, it is suggested to always look for the room of improvement to boost performance despite the feeling that you don’t need that. So, here are the following few tips to speed-up or optimize your AngularJS apps.
1. Carefully Observe your Digest Cycle to Optimize AngularJS
The digest cycle is considered as the best indicator of AngularJS applications performance. It is a cycle that works on a loop to check and monitor the changes in the variables. Hence, as much shorter the digest cycle is, the faster your application will run.
It will definitely boost the performance of the application and deliver good results from the customers. A fair performing application will automatically attract more users and give a boost in the market.
2. Limit your Watchers to Optimize AngularJS
Implement data-binding at any time, and with this, you can create more $$watchers and $scopes, which will extend the digest cycle. Too many $$watchers can increase lag time, therefore prefer limited use of it or avoid using it as much as possible.
As we learned in the above point, the small digest cycle will result in an optimized AngularJS performance. Hence, make sure to limit your watchers and prevent long digest cycles.
3. Limited DOM Access
The access of DOM is quite expensive, so try to maintain the DOM tree smaller. If it is possible, then don’t try to modify the DOM and don’t set an inline style to avoid the reflow of JavaScript.
Limited DOM access can optimize AngularJS performance and minimize the expenses too.
4. Use ‘scope.$evalAsync’ to Optimize AngularJS
While the digest cycle is already running and you try to activate it manually, then you are going to get an error. Therefore, to prevent yourself from this situation use “scope.$evalAsync” instead of $apply, to initiate the digest cycle manually.
This code queues up the operation to be executed at the end of the current cycle without setting off the new or current one. It will save you from getting errors and increase the lag time of the digest cycle.
5. Use the Chrome DevTools Timeline and Profiler
Chrome’s both the DevTools Timeline and Profiler can help find bottleneck situations and perform a guide to optimize efforts. Both the tools work effectively to optimize AngularJS application or web performance.
Chrome DevTools or Chrome Developer Tools are web authoring and debugging built into the browser. It provides access to web browsers and applications to the developers for deeper access. These tools allow developers to perform numerous tasks ranging from testing the viewport on the mobile device to editing the website or even measure the performance of any individual asset or the whole website.
6. Use Lodash to Optimize AngularJS
The Lodash tool in AngularJS allows developers to quickly write application’s logic to improve the built-in AngularJS methods and enhance the application’s performance. However, suppose the Lodash tool is not used in the already existing web application to optimize its performance. In that case, the developers can rewrite the method on their own by using native JavaScript.
This tool allows developers to optimize AngularJS web application performance apart from that they can write the method on their own to do so. It is a very effective tool for AngularJS development.
7. Disable CSS Class and Comment Directives
While creating a directive, the developers can assign it to be used as an attribute, element, comments, or CSS class. However, if you don’t require comment directives and CSS class, it can disable them to boost the AngularJS application’s performance and optimize AngularJS performance.
8. Prefer using One-Time Binding only
In the latest version, i.e., Angular 4.0, this feature is not available. However, if you are using older versions than this, then you may be able to take advantage of on-time binding.
So, to implement or exercise this feature, just add a double colon before the value. If it is done correctly, the value will get resolved once and disappear from the watchers list. This feature was first introduced in the version of AngularJS 1.3, and is not available in the latest 4.0 version.
9. Disable Data Debugging
The Batarang and Protractor tools depend on the data binding and scopes with which AngularJS attaches to DOM elements. Therefore, after finishing debugging, try to disable the extra data so that it doesn’t drag the application performance.
Disabling the data debugging optimizes AngularJS performance and increases the performance of the web application.
10. Avoid ‘ng-repeat’ to Optimize AngularJS Development
Excess use of ‘ng-repeat’ directive can drastically affect the overall performance of the web application. However, to minimize its effect, there are alternatives too. For Example, instead of using ‘ng-repeat’ to render the global navigation, the developer’s can build their own by using the ‘$interpolate’. It is a provider to render the template against an object before converting it into a DOM node.
11. Use ‘ng-if’ or ‘ng-switch’ instead of ‘ng-show’
The directive ‘ng-show’ simply toggles the CSS display on or off for a specified element.
To remove an element from the DOM, the developers must use ‘ng-if’ or ‘ng-switch’. It is another brilliant tip to optimize AngularJS web applications.
12. Use ‘$cacheFactory’ to Optimize AngularJS
If you need to store the data that might be required to be calculated after a period of time, then prefer using the ‘$cacheFactory’ directive. It is quite similar and works like any other memoization method.
13. Use ‘console.time’
While facing any issue in debugging, ‘console.time’ tool in Chrome DevTools is a wonderful option or tool for calculating the execution time and other performance benchmarks.
It is a brilliant and very helpful tool in managing issues while debugging and calculating different performance benchmarks to optimize AngularJS development.
14. Use $filter to Optimize AngularJS
AngularJS development in a web app runs the DOM filter twice during each digest cycle. In the first DOM filter run, it detects changes, and in the second run, it updates the values that have changed. However, to save time in this whole cycle process, the $filter provider allows pre-process data before it is sent to the View and, after that skip the DOM parsing process.
It is a great tool to optimize the speed of the web application and the AngularJS development process to save time and improve application overall efficiency.
15. Use ‘$watchCollection’
While using $watchCollection, only two parameters are a great choice, but three or more than three parameters are like a crowd. The addition of a third parameter forces AngularJS to go through a deep checking and results in the requirement of a lot of resources in use.
The developers can include excellent work with having around the ‘$watchCollection’. It works as a third parameter for $watch. Despite that, it checks the first layer of each object’s properties, so that it won’t slow down the overall speed and performance of the AngularJS web applications.
16. Debounce ‘ng-model’
Debouncing inputs by using directive ‘ng-model’ can play a vital role in limiting the digest cycle.
For Example, implementing ng-model-options=”{debounce:200}” can ensure that the digest cycle doesn’t run more than once in every 20ms. It is a great tool to limit the digest cycle and ultimately optimize the performance of the AngularJS development.
17. Rigid Scoping
Try to keep all your variables scoped tightly. With this, JavaScript garbage collectors will free up the memory that is getting occupied uselessly and in a frequent manner to fasten the process. It will help provide the required resources to the upcoming processes and speed up the application’s working. It is a very easy and common way to optimize AngularJS performance.
18. Infinite Scrolling or Pagination
It is a very effective and brilliant optimization strategy as if everything fails; then it will work. You can minimize the number of looped elements by implementing the Infinite Scrolling or Pagination technique. To serve this purpose, AngularJS has a directive called ‘ngInfiniteScroll’.
19. Use Pure Pipes to Optimize AngularJS
AngularJS uses pipes to display model values on the UI in a little different format. For example, ‘date | shortdate’. Here, the shortdate filter will convert date objects in the small format like ‘DD/MM/YYYY’. Pipes are used to slice and dice the data for display purposes. The Pipes are categorized into two parts, i.e., “Impure Pipe” and “Pure Pipe”.
The difference between Pure and Impure Pipe is that Impure Pipe can deliver multiple output for a similar input over time. However, the Pure Pipes means a function that can produce similar output for the same input data.
AngularJS has some inbuilt pipes, and all of them are pure in nature. Therefore, when it is preferred to binding evaluation, each time Angular evaluates an expression and then applies the pipe over it (if exists).
AngularJS Performance and Testing Tools
It is always possible and efficient to adopt best practices from the initial phase instead of going back and implementing changes. Before starting coding, plan carefully about how to limit bindings, expensive directives like ng-repeat, and watchers. Apart from that, there are multiple tools that help to optimize AngularJS performance and are good testing tools.
1. Protractor
Protractor is a very powerful and automated end-to-end Angular Testing Tool. The Angular team developed this powerful tool. Protractor is built with the combination of some brilliant technologies such as Selenium, NodeJS, Jasmine, Mocha, Cucumber, and webDriver.
It allows running automated end-to-end testing with an ease. The combination of technologies boasts all the features. With this, developers can use the Selenium grid feature to run simultaneously on multiple browsers. However, by using Jasmine and Mocha, you can write your own test suites.
2. WebdriverIO
WebdriverIO tool allows controlling a browser or a mobile application only with a few lines of code. It makes the test code look simple, concise, and easy to read. This integrated test runner allows developers to write asynchronous commands in a synchronous manner. Due to which, the developers don’t have to care about how to avoid the racing conditions. As well as it also takes away all the complicated setup work and manages the Selenium session.
3. TestingWhiz
TestingWhiz is one of the most user-friendly test automation tools to optimize AngularJS because of its codeless scripting feature. This tool offers an end-to-end testing solution to test the AngularJS web and mobile applications. Its codeless scripting feature makes this tool popular, especially among the non-programmers.
Conclusion
As we have witnessed, Web Development is changing rapidly due to the introduction of new technologies and updates in the JavaScript frameworks. Hence, to gain maximum benefits from these frameworks, being a developer, you must keep optimizing the application performance on a regular basis. By optimizing AngularJS performance, the developers are also able to get more with less coding.
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