AngularJS to Angular Migration - The Ultimate Guide
October 15, 2024•19 min read
Experienced and professional companies always stay on top of global technology trends. Here is an era when AngularJS to Angular migration is a necessary procedure, not a fad. With the successful development of the second version of the technology from Google (Angular 2+), more and more businesses are thinking about switching to the new framework.
Delaying decisions on this critical migration could put your company at risk, as in January 2022, AngularJS is officially dead.
Over the past two years, the demand for migration has skyrocketed as founders have begun to realize the growing risks of sticking with outdated technologies — some even fear the potential failure of their businesses.
The Frontend Company is one of the leading Angular migration service providers with extensive experience in handling a wide range of cases and successfully completing numerous migrations.
That is why my team and I created this guide for you.
By reading it, you will understand the benefits of the Angular JS to Angular migration, what resources you need, what steps to take, the potential challenges you might face, and, most importantly, how to avoid critical mistakes during this complex process.
Take your time, do not push forward, and let's work it out together.
What is AngularJS to Angular Migration
Migrate AngularJS to Angular contains a bunch of technical tasks, but mostly, it is a strategic decision that requires detailed planning and trustworthy partners.
Migration is a cooperative process where your role extends beyond just financing the project. You must work closely with a professional development team to align the migration goals with your business needs and make multiple decisions.
This process demands preparation, time, and resources.
It involves:
- evaluating the current state of your application
- defining clear objectives
- ensuring that the migration aligns with your long-term vision.
But the most crucial is finding a reputable company, such as The Frontend Company, to guide you through all processes. Together, we will create a roadmap, deal with potential challenges, and make informed decisions at every stage. And you will be part of it.
7 Key Benefits of AngularJS to Angular Migration
First, let's examine the key advantages of AngularJS to Angular migration, as understanding them may reveal the true value of this process.
1. Modern Architecture to Grow Business
Angular's architecture is based on a modular, component-oriented structure, where closely related elements can be stacked to create a module. Why is it cool? This design allows each module to function as an independent functional unit, improving code reusability and making it easier to manage and reborn services over time.
For your business, this means faster development processes, lower maintenance costs, and growth potential. By operating on modern technology, you can deliver top-tier user interfaces and outperform your competitors who hesitate to make the step up.
In contrast, AngularJS's traditional MVC (Model-View-Controller) architecture is less flexible and requires more effort to adapt to new requirements — especially now that AngularJS is no longer supported.
Note: You can see some of our case studies. We used Angular for projects such as Photobell, Parloo, and Frest. You can see what came out of this and evaluate the performance of products created with this framework.
2. Less Chance to Make Mistakes During Development
Since AngularJS uses familiar and understandable to most devs JavaScript, it allows them to set up various products simply. Even so, AngularJS has no type-checking function, meaning that compile-time errors often go undetected.
Angular, built on the TypeScript language, is more structured than AngularJS and provides essential error notifications to developers during code compilation.
TypeScript's type-checking feature flags potential issues when coders write something wrong and reduce the likelihood of bugs in the final product.
3. Improved Data Binding for Faster Development
This feature simplifies developers' work and speeds up the delivery process. In AngularJS, connecting data across the application was more limited, often requiring additional steps.
Angular (starting from version 2.0) improves data binding, giving developers direct access to elements and allowing them to connect data with fewer steps and reduce time and costs in the long run.
4. Dynamic Components for Better User Experience
Angular supports dynamic components that are not defined at build time but instantiated and positioned in the application during runtime. For example, different modules or windows can only be displayed when the user taps the button or screen.
In contrast, AngularJS relies on a more static structure, where components and templates are usually set in advance.
Since components in Angular 2+ can be shown only when they are truly needed, the application can run faster and consume fewer resources, especially during the first loading.
Note: The salary difference between Angular and AngularJS developers is not too big. The average yearly wage for an Angular programmer in the United States is $120,000. At the same time, an AngularJS specialist earns about $110,044 per year. This amount is without possible bonuses from employers.
5. Better Scalability and Page Loading
AngularJS decreases the development time and effort thanks to features such as 2-way data binding. However, this also means that the page load can take longer, as it creates additional processing on the client side, especially in larger applications.
Angular offers a more efficient structure with an improved change detection mechanism that handles complex data updates better.
It gives faster performance and a more responsive user experience.
For businesses with large-scale applications, Angular's architecture and performance optimization are significant reasons to migrate, as they improve user experience and strengthen the overall impression of your product's quality and reliability.
6. Advanced Tools and Faster Development Cycles
When it comes to tools, Angular is the clear champion over AngularJS.
For example, Angular includes an official CLI (Command Line Interface) that simplifies creating, managing, and optimizing projects.
CLI allows developers to set up new projects seamlessly and maintain them while also building optimized bundles for production environments.
Moreover, Angular's compatibility with the TypeScript programming language and Visual Studio offers influential advantages. TypeScript boosts code security and maintainability, while Visual Studio provides features to streamline various development cycles, resulting in faster project delivery and more manageable budgets.
Among the list are tools like Codelyzer for code verification, NgRev for analysis, and Augury for debugging, further supporting efficient, reliable development and benefiting project timelines and quality.
7. Better Mobile Support
When the number of smartphone users grows yearly, ensuring that your product performs well on mobile devices is vital. A newer version of Angular allows you to build native-like apps, providing an outstanding user experience that AngularJS cannot offer.
Unlike AngularJS, Angular 2+ includes both an application layer and a rendering layer, allowing developers to implement necessary components seamlessly across mobile platforms.
Additionally, Angular 2+ supports reactive programming, simplifying complex data handling and allowing to manage data flows more effectively.
Short Summarize
Undoubtedly, AngularJS to Angular migration gives many advantages that can modernize your product, eliminate technical debt, and improve your business outcomes.
If the benefits above have convinced you of the importance of migrating to Angular and you are ready to do it, the next step is to choose one of the two migration ways.
Choose of Migration Ways: Adapt or Rewrite
The 1st way of AngularJS to Angular migration is to implement hybrid solutions where old AngularJS and new Angular run together. This approach enables the replacement of components and features without completely overhauling the entire system.
Pros to this approach:
- Speed: Developers can operate individual interface elements and quickly fix issues on specific pages or tools. It can be beneficial if your business handles high traffic and cannot afford extended periods of downtime. By making real-time updates, you maintain continuity while gradually completing the migration in the background.
- Safety: Since the development team will write the new code alongside the old AngularJS code, there is minimal risk of breaking the live application. It is especially useful for new developers who haven't worked on the project before and keeps the live system stable throughout the migration.
- Smooth transition. Over time, your project will gradually transition away from the outdated AngularJS framework and fully embrace the best features of Angular. It will enhance the quality of the interface, boost overall business performance, and protect your system from potential failures while helping avoid technical debt.
Cons to this approach:
- Maintaining legacy code: The hybrid approach keeps the current system stable, but the old AngularJS modules will need ongoing maintenance as long as they're in the system. Any improvements and modern features will only affect the new Angular parts, leaving the legacy code untouched and potentially raising long-term maintenance costs.
- Time-consuming for developers: Supporting both AngularJS and Angular within the same project can be time-consuming. Devs need to work on maintaining the old system while simultaneously developing new features in Angular, which can slow down the migration process.
- Technical complexity: Developers who are proficient in both AngularJS and Angular are scarce on the market. Finding talent with the necessary skills to adapt features between the two frameworks can be very challenging. Most developers focus on the latest technologies, leaving behind older knowledge about dead frameworks like AngularJS.
The 2nd way of migration AngularJS to Angular is to have two fully separated applications.
Pros to this approach:
- Rethink Business Flow: Building your product from scratch lets devs update previous design or process issues, such as complex registration or lead generation flows.
- Hear Your Clients: This approach gives you the greater creative freedom to build a solution that aligns precisely with your business goals and clients' needs.
Cons to this approach:
- It can take much time: Building an entirely new product can be time-consuming, especially for larger systems. Even with complete preparation, detailed documentation, and experienced developers, the timeline could extend to a year or more.
- Increased Costs: Developing a completely new solution from scratch might come with a hefty price tag, especially if your project needs additional resources or specialized developers.
- Parallel Development Risks: Running two projects together may require pausing or slowing down current tasks, impacting productivity and delaying other priorities.
Short Summarize
Choosing the proper migration way is not easy. And making it without good advice is even more challenging. Remember, you are not alone on this road. The Frontend Company is always here to support you and help you choose the best migration path.
After determining which of the two ways best suits your needs, it is time to begin the preparations and create AngularJS to Angular migration step-by-step plan.
Migration Plan: How to Prepare for AngularJS to Angular Migration
The next step is carefully planning and preparing for a smooth transition. Doing it is crucial to speed up the migration process and reduce potential issues.
Here is what an effective AngularJS to Angular migration step-by-step plan should include:
1.Project Assessment and Detailed Planning
The preparation for the migration process starts with assessing your project's current state and the goals you are aiming to achieve. Together with the development team, you need to identify existing challenges, technical debt, and any obsolete code that might impact the migration.
Thanks to this structure, every migration step will go without disruptions, keeping the project aligned with your business purposes.
2. Selection of Tools and Libraries
The next step is selecting AngularJS to Angular migration tools and libraries for the process. The best thing for the devs team is to pick a list of tools they will 100% use in their tasks. And additionally, choose toolkits that the crew can use in case of problems with the core toolset.
Working closely with the developer team, you will review project requirements and choose tools like ngUpgrade for hybrid applications, Angular CLI for efficient workflows, and Webpack or Gulp for build processes. Most of these tools are open-source and free, but some specialized libraries or plugins may require paid licenses.
In such cases, licensing costs are typically the client's responsibility and should be considered during the planning phase to ensure they align with the project's budget.
3. Assigning Roles and Responsibilities
We are not going to detail this step for two reasons. First, we don't know how tasks will be shared within your development team. Second, if you are planning to work with an outsourced development team, you don't need to think through this phase independently.
My only advice is to keep a clear division of roles within the team. Do not assign tasks to specialists in a chaotic manner. Otherwise, you will be unable to find the person responsible for this or that amount of work.
For instance, developers with frontend expertise may focus on implementing new features while others handle migrating legacy functionality. QA specialists may also be assigned to test updates, ensuring each migrated component performs reliably and continuously.
4. Setting Up a Hybrid Environment
If you have chosen a parallel migration method, you must set up a hybrid environment. In this setup, both AngularJS and Angular operate within the same application, allowing a smooth and gradual transition. Using tools like ngUpgrade, the development team can bridge the two frameworks, enabling individual components to migrate without disrupting the application's performance.
For clients who prefer rewriting the application from scratch, this step is unnecessary and can be skipped.
5. Managing Expectations and Understanding Migration Risks
Before migrating AngularJS to Angular, make sure to manage expectations around timelines, budget, and potential risks. The migration team should anticipate possible delays by identifying factors that could impact the timeline, such as technical complexities or the need for adjustments.
Data protection and security strategies should also be developed to minimize risks and ensure seamless service during the migration.
Additionally, clarifying which functions and components need immediate attention and which can be postponed will help the team focus on critical elements that directly impact users and business goals.
Note: Your goal when thinking about an AngularJS to Angular migration plan is to minimize the development time of a hybrid web application. Why? The longer a project is in a hybrid mode, the more difficult it becomes to maintain. Two code bases result in users getting extra megabytes of JS-based code. It negatively affects the loading speed. In addition, coders have to deal with two frameworks at once while still releasing updates and maintaining the web service.
Short Summarize
Our example of the AngularJS to Angular migration step-by-step plan can hint at what programming team you want to hire. It is enough to check some points, tools, and ask in detail why the developer has chosen this path or another.
There is no single proper roadmap for every migration process. However, a pro will readily tell you why he acts one way or another.
When your AngularJS to Angular migration plan is ready, your role shifts to trusting the development team and controlling the process to ensure everything proceeds according to schedule.
However, there are numerous challenges and pitfalls that may arise. Being aware of these potential issues and prepared to address them will help you navigate the migration process successfully.
The Most Common AngularJS to Angular Migration Pitfalls
Migration Pitfall #1: Possibility of Breakdowns and Performance Slowdowns
During the parallel operation of a product on both AngularJS and Angular, there is a risk of errors that may lead to disruptions and slowdowns in the application or platform. You must be prepared for this possibility and act swiftly if it occurs.
Regular testing and continuous monitoring of the product's status are necessary to quickly detect any issues and report them to developers for prompt resolution.
Migration Pitfall #2: Client Database Vulnerabilities
AngularJS is dead, and many of its libraries are no longer supported, which can lead to vulnerabilities through which attackers could access client data. This risk can severely impact the company's reputation.
A security audit during the preparation phase is essential to eliminate outdated dependencies and vulnerable components. The development team should implement additional security measures, such as updating libraries and using modern encryption and data protection techniques.
When working with a development company, make sure to address these points and confirm that this step receives close attention, as overlooking it could pose serious risks to your product.
Migration pitfall #3. Challenges with Automation in Migration
In some projects, devs can use template loaders and set up S2S (source-to-source) compilers. Typically, this is possible for small web apps or products where part of the backend doesn't need to be reused in an upgraded system.
There are situations when making the backend work without failing; you must redo part of the frontend. We had such a situation only once when the application backend was based on ASP.NET. In that situation, we had to do the AngularJS to Angular migration by writing the frontend part of the source code.
Methods for automating the migration process speed things up a bit. But in complex apps, it's better not to use them. If you suddenly encounter a bug at any stage, it won't be easy to find its cause quickly.
Migration pitfall #4. Problematic Implementation of Complex Functionality
For improvements in technology when working with SaaS, you need to think about the roadmap in a way that doesn't affect the interests of users. Many web applications are shared by thousands of people at the same time, both for studies or task management and for business. If the AngularJS to Angular migration team does something wrong, it will lower the quality of service and precede severe business losses.
The following requirements must be met to avoid pitfalls:
- brainstorm and find several solutions to the issue;
- make sure that the deadline for the migration is not burning;
- find a team of specialists who have done similar projects.
There is no one-size-fits-all solution in situations where you need to implement complex functionality. You must think of a new way to enhance each time, focusing on the starting architecture and user needs. The task of the programming team in such a circumstance becomes additional work on dependencies and preserving the business logic of the web app.
Migration pitfall #5. Not All Tool Kits Are Equally Effective
It is another common trap that hinders many in the AngularJS to Angular migration process. The tools list is just a tip for companies and devs planning to migrate. There is no single toolkit capable of handling different types of challenges. So, it's vital for teams, on the one hand, to have a cheat sheet with a set of valuable tools. On the other hand, they are not always relevant to current projects.
Typically, this happens with instruments for outdated AngularJS versions or the latest Angular ones. Not all tools will have any good compatibility; therefore, during migration, one has to look for equivalents and urgently adjust the selection of solutions. The same goes for libraries. Abandoned or obsolete libraries create bottlenecks to the code, not contributing to its successful switch.
Migration pitfall #6. Lack Of Preparation and $scope
Angular 2+ is missing the $scope object, so it's critical to get rid of it for a successful AngularJS to Angular migration. Although this step seems obvious and simple to many people, experts do not always consider it at the preparation stage.
What is the danger of such a pitfall? Loss of time. If the coders miss $scope in the source code, they need to go back a few steps and run migration preparations harder. Such a situation has a solution, but it's better not to waste extra hours on nuances like this.
Migration Pitfall #7: Customization and Multitenancy Problems
For web services and structurally complex applications, the headache of AngularJS to Angular migration is multitenancy. In some projects, the development team needs to provide customizations specifically for each client's needs.
Customizing settings for each person while keeping the service highly adaptable and ensuring that some functions can be added on demand isn't easy. You can manually specify patterns, but it's tough to find a solution and keep the interface the same regardless of personalization.
If you solve the issue wrong, the web application interface will flop, and the business logic won't be preserved. Transferring the source code from one framework to another is not 100% successful in these cases.
Short Summarize
Now you know the common pitfalls that can arise during migrating AngularJS to Angular. When consulting or communicating with your development team, make sure to discuss each of these points.
Let them know you are ready for these challenges, and ensure you receive clear answers to all your questions. This preparation is crucial for a successful migration.
Now, we want to share the key technical stages and show how to migrate AngularJS to Angular from the inside.
These tips include a wealth of technical information that can be especially useful for developers. If you are not a technical specialist, feel free to skip the section below and move on to the next.
How to Migrate AngularJS to Angular: Developers Tips
Stage 1: Building and Configuring the Web Application
When we migrate outdated AngularJS projects to the latest versions of Angular, we use the Angular CLI for work. There's no secret here why this command-line interface (CLI) tool is preferred for Angular 8 and above for such web products.
First, this CLI has all the necessary commands that programmers will need at various stages of development. You can see them on the official page using the link in the paragraph above. Here, you will find solutions for linting and testing, as well as a built-in webpack for loading modules. You don't need to use a third-party solution.
Second, since there are many things in the CLI, you can't do without builders. These functions will help you to simply and quickly perform complex processes and figure out how to build a webpack for unit tests, run a server, etc.
You should use the ng run command to start the builder.
Necessary: the builder code is defined directly by the npm package, and for building or testing, you will have to use an application programming interface (API) called Architect.
Of course, things don't always go smoothly at work, and there have been situations where using the Angular CLI was impossible.
For example, a hybrid web application supports elements and features outside Angular. When upgrading to version 8+, we had to give up the handy CLI; instead, we switched to Webpack or Gulp.
What do we do with these tools?
Webpack is an easy-to-use module builder that can analyze the modules of your web project and create dependencies. It helps us put modules together correctly, reducing the runtime of some development processes.
Here, we feel it would be better not to mislead you and tell you how to use this tool step by step. The main reason for such a decision is that even within our company, we use different versions of Webpack. Technical nuances and algorithms of actions for this builder are better to read in the official documentation.
What about Gulp? We don't use it often. However, in our guide about AngularJS to Angular migration, it is relevant to talk about this tool. In general, Gulp automates routine development tasks.
Stage 2. Configuring Template Loading for Smooth Migration
In hybrid web projects, you must support template loading for two frontend frameworks simultaneously. Since both technologies use HTML templates, you usually don't need to upload files separately. However, in some cases, it's still essential to ensure separate template loading, depending on the specific requirements of the web product or service.
If you're lucky, you can use templates, and everything will work fine. Extremely rare, but we had encountered such projects when loading patterns went according to the canon in theory and practice.
In general, The Frontend Company coders use existing templates as a basis during the development process to create custom templates in Angular.
That is our biggest secret of success in the context of how to migrate AngularJS to Angular. Such an approach takes a bit more time, but we are 100% sure that every template works appropriately.
Before you utilize the recommendations described above, consider whether this is relevant to your web project.
If you need an experienced team to adapt templates and ensure a smooth, secure AngularJS to Angular migration, contact us today. Let us help you find the best solution for your project's needs.
Stage 3. Setting Up the S2S Compiler (for the lucky ones)
The following section may not be universally applicable, as these recommendations are intended for optimal conditions. Here, we will explore migrating AngularJS to Angular using the S2S (source-to-source) compiler.
We will use the TypeScript transcompiler to convert one programming language to another. Only two functions will need to be enabled beforehand:
You do this step to make the decorators work correctly. If you don't prepare the S2S compiler to handle the TypeScript-based framework, the migration mechanism you've fine-tuned up to this point will not start.
For us, everything is excellent about the TS transcompiler: our specialists can create the necessary solutions and write code independently without thinking about how to bypass the next crutch of development.
The disadvantage is that you spend more time and effort on the process.
From our experience, the out-of-the-box solution didn't always do what we expected in some projects. In such a case, we had to look for workarounds for blockers frantically; it took a lot of time, too.
Interesting: Some web applications may already use that S2S compiler, which will then help programmers convert the JavaScript-based code into a TypeScript-based one. Using that compiler in such a scenario would make more sense than redoing everything.
Stage 4. Customizing Polyfills for Browsers
At this stage, half of the work is behind us, and we can see the finish line somewhere in the distance. After setting up templates and selecting transcompilers, it's time to start setting up browsers.
You shouldn't have any difficulty; just fine-tune the polyfills according to the recommendations. The advantage is that the official Angular team has shared a guide that helps you organize everything perfectly, or at least okay.
The challenge here is that the number of browsers and their versions is growing. Before, there were 2-3 popular browsers, but now, the same person can use different browsers on all devices. Rather than confining browser support manually for each version, it is easier to customize polyfills. They help enable specific functionalities as needed, significantly improving user experience components.
Note: Different web and mobile browsers have specific polyfill configurations. You should first check the official documentation and only then get down to business. Also, keep in mind that you are bound to run into missing polyfills for outdated browsers. Then, you will have to do some brainstorming.
By the way, we have a case in point about outdated browsers.
One day, our colleagues faced the problem that Internet Explorer (IE) 11 did not support ES-2015. As you can imagine, later features weren't available either. It was clearly the time when they couldn't do without polyfills.
The application developed by colleagues did not show any errors in other browsers. However, as soon as IE11 was launched, chaos began. At that time, the programmers needed to pay attention to this browser version, even though it was very outdated compared to other solutions. The team had to dig out the polyfills.ts file and import all the necessary polyfills into it. The devs also included custom properties CSS as an add-on. After that, everything worked properly.
Stage 5. Setting up Bootstrap
We often act traditionally for many projects during this process and bootstrap each part of the web app. Here, we stick to the official recommendations; we load Angular code first and then AngularJS source code. It will be easier to use UpgradeModule for end goals with this sequence. Sadly, for hybrid web projects, we have to do bootstrapping manually.
Note: For everything to work like clockwork, you'll have to switch the AngularJS code to use angular.bootstrap by hand at the preparation stage. It is important to do so before the development team starts using the hybrid web project. Otherwise, you can't avoid needless complexities and roadblocks in the other stages of the migration.
Once the programmers finish preparation and enable manual Bootstrap for the AngularJS-based project part, we can move on. The Frontend Company team usually creates app.module.ts, and then, using the NgModule class and the import option.
The created module helps import the obligatory module for the browser app and the UpgradeModule. After that, it's crucial to use DoBootstrap to load the AngularJS part of the project. This method follows the same lines as angular.bootstrap.
That's not the end of the story on how to migrate AngularJS to Angular. After coders have made all the recommendations described for bootstrap, they will finally have to bootstrap AppModule. The Angular framework team recommends doing this via the browser dynamic platform.bootstrapModule method.
Stage 6. Adjusting Routing
Our experts are most involved with the ngUpgrade library.
The easiest option would be to define routes for both JS-based and TS-based frameworks. There's nothing out of the ordinary here; we proceed as usual. Then, we create and name a particular class, primarily according to the project. It will be simpler in the future to understand what was done in the routing process and for what purpose.
Besides the new class for linking the two frameworks, we write the same class inside the main component in the hybrid app. After that, our team updates the root component, which includes the Angular router.
That's the end of our experience of migrating AngularJS to Angular. Then, depending on the specifics and industry, The Frontend Company team works on additional steps. Above, we share with you six basic steps, which are regularly repeated during the migration of different web projects.
If you need help with migration or professional advice, please get in touch with our managing partner, Viktoria.
Final Word
Wow, I wrote a lot more than I thought I would. I hope it was informative though!
Undoubtedly, the AngularJS to Angular migration process is complex and demands time and resources. However, it becomes much more manageable when you have a reliable partner with experience in various migration cases by your side.
If you've read this guide to the end, thank you first; second, you are better equipped to handle these processes, more informed, and far more prepared for the journey ahead.
Remember, postponing this transition is like sitting next to a ticking time bomb for your business — at any moment, issues could arise, creating major setbacks. Don't wait for that moment. Start your migration today!
Insights for AngularJS to Angular Migration
- For each web app, the number of steps and tools for migration varies; there is no one-size-fits-all template for how to migrate to the latest platform;
- If you do not consider a roadmap for the switch in advance, the work is delayed, and the number of tasks increases;
- The Angular Team has not answered in the official documentation all the questions that coders may have;
- Despite some development hurdles, the migration process is not so terrifying and has many pluses for many web projects;
- In some cases, building a hybrid application is better than making a web product from scratch;
- Insufficient understanding of how JavaScript works and little programming experience slows down the process a lot, so you need to involve technically savvy experts;
FAQ
Alex Vasylenko is the founder of The Frontend Company, DBC and several other successful startups. A dynamic tech entrepreneur, he began his career as a frontend developer at Deloitte and Scandinavia's largest banking company. In 2023, Alex was honored as one of 'Top 10 Emerging Entrepreneurs' by USA Today.
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