11 Tips for improving Angular JS Performance

January 11, 2019

11 Angular Performance Tips

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Angular JS is a JavaScript-based open source framework developed by Google and used for building Model-View-Controller-based applications.

This framework is mostly used to build Single Page applications and is always updated regularly.When you need to create and manage dynamic frontends for web applications, the best tool to use is Angularjs.

In a way, angular js eases the coding-load of the developers as it automatically takes care of things like DOM manipulation and AJAX glue. There are numerous benefits why companies with large teams adopt angularjs.

One main reason for this is that angular js is fundamentally built on functionality-first mindset, which makes it the best option in top-down development process making it easy to divide labour in large scale projects for Angular Js Developers.

As web traffic and performance is single-handedly supported by angular js, isn’t it crucial to understand and learn what goes into improving its functionality?

Therefore, we offer top 11 quick tips for improving angular js performance below:

1. Monitor your digest cycle:

The simplest and the most feasible way to measure the performance of your Angularjs app is your digest cycle. Therefore, it is important to monitor your digest cycle and keep it short. The reason being, the shorter the digest cycle, the better and faster your application will run.

2. Keep a cap on the number of watchers:

The number of watchers you create the longer it takes in the digest cycle. As the angular world revolves around the digest cycle, it is important to focus on this. It is a best practice to reduce the number of $$watchers and $scopes will shorten the time taken in the digest cycle.

3. Consider using a one-time binding:

This is because when you use a one time binding, these expressions will stop recalculating once they are stable after the digest cycle when the result of the expression is a non-defined value. Instead of evaluating in loops in the digest cycle, the expression is evaluated only once. However, you would also have to note to which version you can apply these changes and not. For instance: the one-time binding feature introduced in Angularjs 1.3 is not available in Angular 4.0

 

4. Use scope.$evalAsync to avoid errors:

In order to avoid errors while the digest cycle is running, you could use scope.$evalAsync instead of $apply when running the digest cycle. By using this, the operations will run faster by queuing them at the end of the current cycle.

5. The use of Chrome DevTools cannot be overlooked:

From Quick File switching, editing an HTML element, searching within source code to selecting from custom colour palettes and monitor the network performance using the latest developer tools update, the benefits and the usage of Chrome Dev Tools cannot be simply overlooked.

Without which, as a user you wouldn’t be able to experience the ease of developing better, debugging faster and measuring the performance of your application more effectively.

Two best examples of such Dev Tools are CPU Profiler and CPU Timeline.

 

6. Limiting DOM access and focusing on DOM manipulation:

It’s best to limit DOM access in order to save costs. As accessing the DOM can be expensive, it’s advisable to keep the DOM trees small. It is also important to pay attention to DOM manipulation in directives. There are some offenders such as ng-show and ng-hide that can increase the $$watcher counts. If you overlook this step, the watchers from these offenders can easily be stacked up to reach hundreds and thousands inside an ng-repeat.

 

7. Avoiding ng-repeat:

Following the previous point carefully, the function of an ng-repeat is to increase the number of watchers, if not numerous watchers constantly looped over by Angular-things such as true and false.

8. You might be doing something like this:

  1. <div ng-show=”something”></div>
  2. $scope.something = false;
  3. $scope.someMethod = function () {
  4. $scope.something = true;
  5. };

 

Therefore, it is time to reconsider this step.

Overuse of this feature can also bring down the performance of the system. Therefore, one step that can help you avoid this is to use $interpolate instead of ng-repeat. This helps in rendering your template against an object before it is converted to a DOM node.

9. Boost your application with Lodash:

Simple tips and techniques such as these can help you improve Angular js performance and take your system a long way. In other words, by using Lodash you can boost your application performance. Instead of relying on the inbuilt Angularjs methods, you can simply rewrite some of the basic logic. In case your application doesn’t use Lodash, then you would need to rewrite the logic in native JavaScript by yourself.

 

10. For debugging issues, use console.time:

console.time is a great API you can use if your application is struggling with any debugging issues and affecting the Angular JS performance as a whole. If you want to measure execution times and any other performance benchmarks, this could be your go-to tool to use.

11. Disabling debug data:

Similarly, you can disable extra data after debugging as its presence can slow down your application. To improve the performance of your application, you can use tools like Batarang and Protractor, which rely on the data about binding and scopes.

You can disable the debug information as follow:

 

angular.module(‘app’).config([‘$compileProvider’, configureModule]);

 

function configureModule($compileProvider) {

$compileProvider.debugInfoEnabled(false);

}

Another great function of Batarang is to help you profile and track the performance of your AngularJS application. It can help you reduce overhead by lowering your debugging efforts.

12. Filter using $filter:

To reduce the number of steps, you can use a $filter as it saves time by allowing you to preprocess data before it is sent to the View and as a result skips the DOM parsing process. In Angularjs, it runs the DOM filters twice while running the digest cycle. First, to detect changes and second to update the changed values by using a $filter, you can save time considerably.

One bonus point: Use Pagination or infinite scroll:

You can also improve the Angular JS performance by implementing pagination or infinite scroll as this helps to reduce the number of elements that loop over. You can do this by using a directive called ngInfiniteScroll.

If all the above points fail you, then this step can help you. Time and again, this list will serve as a reminder to come back to as it is more clever to employ the best practices that have been tried and tested rather than going back to the logic and making changes.

It’s important to think about limiting bindings and watchers and expensive directives like ng-repeat even before you begin coding.

Bonus Section! Be sure to check following important tools to enhance the performance of Angularjs:

Protractor:

The angular team developed this powerfully automated end-to-end Angular testing tool. A protractor is the result of combining some of the best technologies such as NodeJS, Selenium, WebDriver, Mocha, Cucumber and Jasmine.

As JavaScript is huge, dealing with it and optimizing the performance of Angular which uses JavaScript is not easy. Therefore, by using protractor you can test the web for various scenarios and it also speeds up your testing process as it optimizes the sleep and waits times.

WebDriverIO:

WebDriver IO is more flexible than WebDriver JS and that it is easy to use for non-programmers is a popular belief and a favourite go-to tool for most of the developer community.

To put it simply, it is front-end friendly.  It allows the developers to write the code in the language they are familiar with.  It is a custom implementation of W3C webdriver JSON wire protocol.

Nightwatch JS:

Similar to WebDriver IO, Nightwatch JS is also a custom implementation of W3C webdriver API and it is continuous integration framework based on Node.js and a complete end-to-end testing solution like Protractor. It is useful when writing Node.js unit tests.

Even though Angular specific locator is not supported with Nightwatch JS, we can automate angularjs application similar to selenium.  One main advantage of using Nightwatch JS is that it has its own testing framework and assertion mechanisms.

This reduces a programmer’s burden of choosing a testing framework. Though it doesn’t have many choices for unit test frameworks, it has its own unique testing framework.

TestingWhiz:

It is an intuitive and codeless test automation tool for the web, web services and API testing. Like Protractor and webdriver IO it is an end-to-end testing tool that aids novice beginners as well as seasoned testers.

TestingWhiz is also popular among non-programmers due to its codeless scripting feature. TestingWhiz syncs varying server wait times due to dynamic commands in order to provide end-to-end testing of Angular apps.

Batarang:

This tool is a chrome extension, which comes directly from the Angular team built with an idea to make debugging easier. Some call it ‘the superheroic tool’.

This chrome extension offers performance analysis and a dependency graph which is useful when developing and debugging Angularjs apps and also help in determining which service and element should get the most attention at a crucial time.

Author Bio:

Alex Jone is in a HR and Recruitment at Alliance Recruitment Agency- an IT Recruitment Agency. He specializes in helping with international recruiting, staffing,hire angular js developer , HR services and Careers advice service for overseas and international businesses.

Facebook: https://www.facebook.com/Alliancerecruitmentagency/ 

Twitter:https://twitter.com/career_alliance


11 Tips for improving Angular JS PerformanceTweet This