AngularJS to Angular Migration Guide 2025 | Step-by-Step

Introduction

You're not alone if your business application is still using AngularJS. Many businesses still rely on this once-leading framework, even though Google formally stopped supporting it in 2021. But what seemed like a solid base has subtly turned into a major source of risk for the company. The topic of discussion has shifted from whether or not to upgrade to modern Angular to how to do so without interfering with your business operations.

Despite AngularJS reaching its official end-of-life over three years ago, recent npm statistics reveal that approximately 419,000 applications continue to download AngularJS packages weekly. These aren't just legacy systems; they represent significant business risks for organizations that depend on them.

The migration question has evolved from "if" to "how quickly" it can be accomplished. With the right strategy and modern tooling, organizations can transform their digital assets from legacy liabilities into competitive advantages.

This guide offers a clear, practical roadmap for your migration journey in 2025. We will explore the critical reasons why staying on AngularJS is no longer a viable option, outline the key benefits of moving to modern Angular, and compare the different strategies you can use to get there.

What are the risks of not upgrading from AngularJS to Angular?

If the app is still working, it can seem like the easiest thing to do to keep using AngularJS. But this ignores the growing threats that have made migration an essential need. The framework has achieved its end-of-life (EOL), which means that Google no longer sends it security patches, performance improvements, or bug fixes.

Because there is no support, your application is open to major security holes. Your system is an easy target for cyberattacks since new threats are found but not fixed. Also, newer browsers are no longer optimized for AngularJS, which might make things run more slowly and make the user experience less pleasant. Finding engineers that can keep your old system running is becoming harder and more expensive because the pool of people who know how to use this outdated technology is getting less.

Why does using AngularJS open your business to security issues?

• Unpatched Flaws: Since support ended, new vulnerabilities like Regular Expression Denial of Service (ReDoS) and Cross-Site Scripting (XSS) threaten all AngularJS applications to Angular upgrade candidates. Such flaws remain permanently unless you upgrade from AngularJS.

• Emerging Threats: In 2025, CVE-2025-0716 exposed unsafe SVG sanitization—a risk that will persist for any AngularJS app still in production, highlighting the urgency to migrate AngularJS to Angular.

• Compliance Risks: Using an unsupported framework like AngularJS in regulated industries inevitably leads to non-compliance, audit failures, and costly penalties.

• Automated bots continuously probe the web for older AngularJS code with known exploits. If you don’t upgrade your AngularJS application to Angular, you’re a perpetual target for attackers.

How does Angular compare to AngularJS? (Upgrade From AngularJS for Real Results)

To plan a successful Angular upgrade, you need to know the main differences between AngularJS and Angular. There are two different frameworks: AngularJS and Angular. The upgrade from AngularJS to Angular changes the architecture, coding style, and development experience.

The move from JavaScript to TypeScript is one of the most significant changes. TypeScript adds static typing, which helps developers catch errors early in the development process, leading to more robust and maintainable code. The shift to a component-based architecture also makes code more modular, reusable, and easier to test.

Migration Strategies: Hybrid vs. Full Rewrite

Choosing the right strategy is the next important step after you decide to move. There are two main options: a slow, mixed approach or a full "big bang" rewrite. The best option depends on how big and complicated your app is and how much disruption your business can handle.

The Hybrid Approach (Using ngUpgrade)

The hybrid approach is the best way to go for most big, complicated, and important applications. This method uses an official library from the Angular team called ngUpgrade. It lets AngularJS and modern Angular run in the same app at the same time.

This method lets you move your application over in small steps. Angular lets you add new features, and over time, old AngularJS components are rewritten. People often call this the "Strangler Fig" pattern. The new system slowly takes over the old one until the old one can be completely taken down.

Pros:

• Minimal Business Disruption: Users can still use the application and it works perfectly during the migration process.

• Lower Risk Up Front: The project is divided into smaller, easier-to-manage pieces, which lowers the chance of a big failure.

• Spread Costs Over Time: The investment can be spread out over a longer period of time, which makes it easier to manage from a budget point of view.

Cons:

• Temporary Complexity: For a time, your team will need to manage a dual-tech stack, which requires expertise in both frameworks.

• Risk of a "Perpetual Hybrid": If the migration is not managed with clear goals and timelines, the project can stall, leaving you with a permanent hybrid that has its own form of technical debt.

What are the key steps to upgrade from AngularJS to Angular?

1. Assess your existing AngularJS application: Evaluate app complexity, business risk, and readiness to upgrade AngularJS.

2. Choose your migration strategy: Decide between full rewrite, hybrid, or Angular Elements.

3. Plan your roadmap: Set project milestones, deadlines, and decommission legacy AngularJS parts at each stage.

4. Equip your team: Provide training in the Angular framework, Angular CLI setup, and Angular TypeScript projects.

5. Start with preparatory steps: Refactor legacy code, improve modularity, and implement Angular component directives where possible.

What tools do you need to make the upgrade from AngularJS to Angular go smoothly?

By using the correct tools, you can make your transition from AngularJS much easier and make sure that your existing AngularJS code moves over without any problems.

• Angular CLI: To make components, handle builds, and make your new Angular app more consistent.

• ngUpgrade (the official Angular Upgrade Module) lets you run both AngularJS and Angular code in the same app. This is great for moving to Angular gradually.

• Angular Elements: Turns Angular components into custom elements that may be used in both new and old areas of an application.

• TSLint and Codelyzer are tools for static analysis, making sure that Angular best practices are followed, and finding bugs in new Angular application files and upgraded AngularJS code.

• Protractor, Jasmine, and Karma: These are tools that can automatically test both AngularJS and Angular sections during migration.

• Cypress and Playwright are for modern end-to-end testing after much of the upgrading from AngularJS is done.

• SonarQube or other static analysis tools can help you check your AngularJS project for security vulnerabilities or legacy complexity.

• Use automatic converters, analytical helpers, and official Angular documentation to speed up the migration process.

• Using these tools is important to make sure that your migration goes smoothly, that there are no problems, and that the quality of your existing AngularJS application stays high as you move it to Angular.

What’s the step-by-step migration playbook for upgrading AngularJS to Angular?

Preparation Phase:

• Adopt TypeScript in your AngularJS codebase.

• Refactor large, monolithic controllers and AngularJS modules into smaller, focused units for easier migration.

• Audit external dependencies and ensure compatibility with the latest Angular version.

Hybrid Migration with ngUpgrade:

• Set up a new Angular application using Angular CLI setup.

• Bootstrap the hybrid application so both AngularJS and Angular parts run together.

• Start with upgrading stateless services, then applications to Angular components one at a time.

• Use Angular routes to gradually shift navigation from AngularJS routes as you progress.

Code example: Upgrading AngularJS directive to Angular component

// AngularJS directive

angular.module('myApp').directive('helloWorld', function() {

 return {

   restrict: 'E',

   scope: { name: '=' },

   template: '<h1>Hello, {{ name }}</h1>'

 };

});

// Equivalent Angular component

import { Component, Input } from '@angular/core';

@Component({

 selector: 'app-hello-world',

 template: `<h1>Hello, {{ name }}</h1>`

})

export class HelloWorldComponent {

 @Input() name: string = 'Angular';

}

Testing & Validation:

• Test each upgrade from AngularJS regularly using unit tests, E2E tests, and regression checks.

• Use the official Angular documentation to align with best practices throughout migration.

Optimization & Finalization:

• After the migration, optimize with new Angular features (SSR, standalone components, Signals API).

• Remove all legacy AngularJS code, dependencies, and ensure full compatibility with the latest version of Angular.

What are the most common mistakes people make while moving from AngularJS to Angular?

• Not realizing how hard migrating is: To move from AngularJS to Angular, you frequently have to do a lot of restructuring on old AngularJS code.

• Inconsistent tool choice: Always use official Angular and open-source migration tools and helpers that you can trust.

• Hybrid trap: If there isn't a clear deadline, hybrid programs can get stuck and build up more technological debt.

• Not enough training for developers: To make sure that your project is successful at every stage of the Angular upgrade, either invest in training your team or hire experienced Angular developers.

What kind of testing plan should you use for an Angular project that has been moved?

• Testing of Units and Integrations: For every new Angular component you make, move or rewrite the tests.

• E2E Testing: After upgrading from AngularJS, utilize Protractor or Cypress to make sure that user flows work as they should.

• Performance and Visual Regression Testing: Tools like Lighthouse and visual testers make sure that your new Angular app works better than your old AngularJS app and looks right.

FAQs

1. How long does it take to switch from AngularJS to Angular?

The time it takes to move from AngularJS to Angular depends on the project. For small tools, it might take less than a month, while for enterprise platforms, it can take more than a year.

2. What are the most typical problems that come up when you move from AngularJS to Angular in the real world?

The biggest problems are old architecture, AngularJS code that is hard to change, making sure that AngularJS and Angular components are the same, and teams who aren't very experienced.

3. Can you run both AngularJS and Angular in the same app using Angular?

Yes. The official angular upgrade module (ngUpgrade) lets you run AngularJS and Angular at the same time until all the features are moved over.

4. Can I utilize tools that work automatically to change my AngularJS code?

Yes, there are a lot of online tools and scripts, as well as AI-powered migration aids, that can do code conversion and auditing automatically.

5. What tools do you need to make sure the migration goes smoothly?

Angular CLI, ngUpgrade, Angular Elements, modern test frameworks, and code analysis tools. You should also always refer to the official Angular documentation.

6. What does Angular do using TypeScript?

By default, Angular is built on TypeScript, which makes it easier to maintain, safer for code, and better for developers than AngularJS's JavaScript.

7. Why is it important for businesses to move from AngularJS to Angular?

AngularJS is no longer being actively supported, which puts your apps at an unacceptable risk. Moving to the most recent version of Angular improves security, performance, hiring new talent, and the long-term health of your business.

Final Thoughts

Migrating AngularJS applications to Angular is no longer optional, it's an essential for any organization that wants secure, future-proof web infrastructure. By leveraging the best resources, official Angular tools, and proven migration strategies, you can upgrade from AngularJS with minimal disruption and maximum payoff.

Start planning today: assess your existing AngularJS app, map your upgrade path, empower your team, and use the official Angular documentation and ecosystem tools. A modern, high-performance Angular application awaits.

Ready to Secure Your Future?

The risks of staying on AngularJS are clear, but the path to a modern, high-performance Angular application is clearer with the right partner. At Hashbyt, we specialize in seamless, efficient migrations that transform legacy liabilities into competitive assets.

Don't wait for a security breach or performance lag to force your hand. Contact our Angular experts today for a personalized migration plan and quote.

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