How to Migrate AngularJS to Angular

So, you’ve decided to opt for modern, future-proof technologies and migrate AngularJS to Angular. It may have been a tough decision as the transition poses challenges such as potential solution shutdown until the release of the new version, feature and API migration, and embracing the architecture of the newer technology.

We at ProCoders know exactly what you’re about to go through as we’ve updated multiple projects in the 9 years of our experience. As a matter of fact, our developers can move your software without having to shut it down!

Sorry, that was a spoiler…

In this guide, we talk about migration approaches, updating framework versions, and how to migrate AngularJS to Angular step by step. Enjoy!

Which Approach in AngularJS to Angular Migration to Choose?

After you study why migrate from AngularJS to Angular and make the decision, you need a well-thought upgrade plan. In our experience, some applications could only be rewritten from scratch, while others only required an update. 

Here are some approaches and factors leading to them that we usually discuss when setting up an AngularJS to Angular migration plan.

Rewriting the software

Legacy applications often need rewriting because they are so out of date that migration can be a serious hassle unless an entirely new code is developed. 

Besides, this method offers benefits such as:

• More freedom to add new features
• More flexible improvements 

However, rewriting also needs more time and a larger budget. It may also become challengings to launch the new app as your team will have to support both versions for some time and make the transition smooth for the users.

Therefore, when planning how to migrate from AngularJS to Angular, consider that rewriting offers more flexibility but may take more time and money since code reusability of the initial app can be low.

AngularJS update

Updating is best suited for large, complex applications which are quite time, money, and labor-consuming. An update is quicker to release in this case. 

Use a hybrid approach, where various parts are gradually rewritten until you have
      a fully successful upgrade. Although this hybrid code is more difficult to maintain,
      it’s a common practice at ProCoders due to the convenience of the result for our
      clients. 

      That is, at no point in the process do you have two parallel applications. Instead,
      the new and the old code coexist until the update process is complete.

Pro tip:

Use a hybrid approach, where various parts are gradually rewritten until you have a fully successful upgrade. Although this hybrid code is more difficult to maintain, it’s a common practice at ProCoders due to the convenience of the result for our clients.  

That is, at no point in the process do you have two parallel applications. Instead, the new and the old code coexist until the update process is complete.

Our advice

• Sometimes an upgrade from AngularJS service to an Angular project may take even more time than building a new app from scratch. That’s because your team may need to reverse-engineer a lot of details.
• When estimating the time required for upgrading, consider the timeframe for the AngularJS app, expecting to spend at least half that time for the transition (e.g., if the initial app was in the works for 1,000 hours, count on 500 hours or about 3 months). 
• Prioritize research, unit tests, and preparation for a smooth transition, acknowledging the opportunity to refresh the UI without making drastic changes that could deter existing users.
• During the upgrade process, it is possible to incorporate both frameworks without having to shut down the application for months by using:
  • The “ng-upgrade” library for gradual migration without rewriting the entire application
  • The “UpgradeModule” class as one of the utilities for bootstrapping and communication between AngularJS’ and the newer modules
  • The “downgradeModule” function to integrate the newer components into a JS app
  • The “upgrade/static” function to do the opposite
• There’s no super-smart converter that will transform the old software into a neat architecture-specific one.

If you need to move a template, a converter may work fine. However, for a professional, effective, and issue-proof transition, it’s necessary to hire web developers with experience in the field.

How to Migrate AngularJS to Angular: Step-by-Step Guide from ProCoders

So, how exactly should you approach moving the solution to avoid data loss and maintain the features? ProCoders professionals have gathered to create an AngularJS to Angular migration step-by-step for you to get familiar with the process. 

Keep in mind this section is NOT the final algorithm we use. Each project is unique, so we always research the details, study your needs and requirements, and then come up with the most optimal decision.

Step 1: Prepare by setting up TypeScript using the @types/angular package. Then, use the TS Compiler and a TS module integration to make the language interoperable with the old JavaScript code.

Step 2: Create a new build of the existing AngularJS app using Angular CLI. Some developers use Webpack directly instead but, in our experience, that’s time-consuming, especially since CLI supports Webpack internally. Copy the AngularJS files to a new folder in Angular.

Step 3: Use the ngUpgrade toolkit to implement a hybrid update and operate two frameworks simultaneously. Utilizing default function parameters will help you ensure backward compatibility and optimize code. This makes the migration process invisible to the users and more convenient for the client.

Step 4: Transfer services and component APIs. You can use the downgrade components to make the newer parts to be available within the AngularJS segment of the project. You might need to rewrite some code while migrating the AngularJS component to the new version of the app. One crucial step is to refactor and adapt the AngularJS module configuration files to align with the updated folder structure and configuration requirements of Angular.

Step 5: At the final stages comes routing, often implemented using UI-Router. ngUpgrade supports this by default, and UI-Router has smooth support for hybrid migration.

Step 6: Due to differences in the JS and Angular template syntax, you may encounter compile-time errors, so make sure to test the app after the migration. Check if all parts of the solution align with the new Angular architecture.

After all the checks and refactoring of AngularJS dependencies, factory(ies) that are substituted with services in Angular, and thorough testing, all you have to do is to update to the most stable versions of the framework when necessary.

How to Update Angular Versions

The Angular framework is constantly updated, there are new versions almost every year, and updating to the latest version is always a good thing due to bug fixes and new features.

Pro tip:

Make sure the version you want to update to is stable. The official website of the framework will update you on all new releases, patches, support, etc.

The official steps of how to update your framework version are:

• Running the ng update command, given the update is simple. The results will show you new availability, along with steps to perform to install them.

Pro tip:

If you need to jump several major versions, it’s better to do it one at a time. For example, in case you want to upgrade from version 10 to 14, it’s better to get to 11 first, then 12, and so on.

That is all! See how easy it is! Our programmers have many more tips and tricks on moving from AngularJS to Angular and updating the versions of the latter. All you have to do is contact us!

ProCoders Case Study in Upgrading from AngularJS to Angular

Here at ProCoders, we’ve helped numerous clients convert AngularJS to Angular. We actually have experts in our pool who are well-versed in AngularJS, which is a rare thing. We have multiple cases with migration, including our Ushahidi and MultiQ. Today, we want to share a part of our interview with one of the most experienced ProCoders developers about MultiQ – a digital signage provider.

Q: What did you do to make the transition smooth?

Andrew: I used a HybridHelper while migrating; the solution allowed both frameworks to function simultaneously so the project was up and running while the developers were working on the migration. I also implemented the Upgrade and Downgrade components that help run AngularJS sections on the newer framework and vice versa.

Q: How did you come to use a HybridHelper and Upgrade and Downgrade components in your approach?

Andrew: The client had already heard about these solutions but had doubts before consulting with me. I reassured them this approach would speed up the process and make it easier tenfold.

Q: How much time did it take?

Andrew: It took around a year to rewrite all the necessary components while the project was live and the client was producing revenue. The migration process itself took a month or so, whereas the original project was completed in 5 years! 

Q: What were the complications and obstacles along the way?

Andrew: There are not many challenges when migrating, but there is one huge pain – scope. In AngularJS, the scope is an object that acts as a bridge between the view (what users see) and the controller (the logic behind it). Since Angular uses a component-based architecture with properties and event bindings instead of scope, the migration process involves refactoring the code to align with the new structure.

Q: How many specialists were working on the project?

Andrew: Only two. Me and Miroslav (a Senior Angular developer at ProCoders) were on the team. Our team’s big advantage is having Senior experts who know the ins and outs of not just the modern frameworks but the outdated ones as well.

The two of us have done what a team of 5-6 less experienced developers would do in the same timeframe.

Q: What was one of the best results for the client?

Andrew: Aside from getting an updated, future-proof solution, our partners at MultiQ were in business the whole time as we didn’t need to close the old resource. This approach has probably saved the client hundreds of thousands of dollars!

So, having a software development partner with experience in these frameworks is a must. But how to find a decent company to provide or augment your Angular team?

How to Choose the Right Development Partner for Migration or Make Suitable In-House Team Extension

There are multiple ways to hire Angular developers, but you need high expertise in the field, which is harder to find. Experience is necessary when deciding whether it’s better to migrate or write an app from scratch, which AngularJS components to rewrite, what utilities to use to make the process quick and smooth, etc.

Here are some things we at ProCoders recommend paying attention to:

• Go through case studies and reviews – you can use sites like Clutch, Upwork, etc. On top of that, if there is a way to contact current or previous customers and find out what they think about the potential partner would be an advantage too. 
• Sign official documentation (NDA, contract, etc.) – this will help you maintain the integrity of your project. 
• Pay attention to the time zone – communication is key during the upgrading process. We at ProCoders always look for ways to maintain continuous communication between clients and developers. We’ve achieved a less-than-30-minute response time during working hours.
• Developer qualifications – the devs must be familiar with both frameworks and well-versed in the techniques used while upgrading from AngularJs to Angular. 

Interview the developers – we at ProCoders always favor our partners interviewing the programmers they will work with. Such an approach sets the tone for the collaboration and liberates the clients from the worries about working with us (if there still are any, which is rare).

One of the first few questions that you must ask the dev is the method they would use during the process. How was their performance rated during their previous migrations? What were the problems that they faced?

Conclusion

At ProCoders, we’ve gathered years of experience with the sole purpose of helping our partners grow and transition to modern technologies. We know that making a decision to migrate AngularJS to Angular, or a decision to convert from JS to TS can be challenging, so we’re ready to assist.

We’ll choose the right way to upgrade your software through migration or by rewriting it from scratch. Our specialists will consider your time and budget plans, using their experience to have an optimal solution for you as we have our second call. 

Our developers, experienced in both frameworks, will handle your app carefully, migrating while it’s still in operation, providing service to customers, and making you money.

If there’s ever a perfect time to slow down and consider moving to newer future-proof technologies, it’s now.