A‌ ‌Developer’s‌ ‌Short-Guide‌ ‌to‌ ‌Angular‌ ‌Migration

Hello, my dear friends! How is your day? Are you ready to read anything interesting today? And now we are going to discuss the topic: “A developer’s short-guide to Angular migration.” I tried to prepare an attractive and valuable topic to discuss. I reckon that after reading this article everyone will say ”Surely, I have heard something about it”. Of course, I will explain some general information with some details for Angular‌ ‌migration. From my point of view, this topic is worth your attention.

I will not taunt you anymore, let’s go!

Changes in the Latest Angular versions

At this point, I will take a look at the process that a developer can follow if he regularly migrates an AngularJS application to its new Angular‌ ‌migration version.

Before you start thinking about the upgrade method, you need to understand the main changes that have come about with Angular. I want to introduce a shortlist of these changes. Here’s a list of what’s new in Angular‌ ‌migration. It’s rather important to recognize these changes when thinking about upgrading:

1. Components

Needless to say, those components are the new building blocks when creating applications with Angular. Most everything is a part, even the application itself.

2. Dependency Injection

Many studies have shown, instead of having a single injector for our whole application, in Angular, each element comes with its injector.

3. Content Projection

This is the new transclusion but joined with the Web Components standard.

4. Dynamic Loading

On the whole, I think the main idea is to enable developers to add new directives or controllers on the fly.

So, as you can see, these changes should be taken into account when thinking about upgrading. Now, it’s time to move to the next point. Be ready!

Steps to Take for Upgrading to Angular

1. Prepare Your Application

Some applications will be easier for Angular‌ ‌Migration than others. A good way is to begin by preparing your AngularJS application to be more fully regulated with Angular. I personally feel that you can perform the upgrade incrementally by running the two frameworks side-by-side in the same application. Then, you’d move the AngularJS elements to Angular one by one. For this, Angular gives an upgrade module that has been created to support incremental upgrading.

First of all, I recommend you to follow these steps. They should make the migration much easier:

Implement good practices presented by the Angular Style Guide

The guide also includes good models of how to create your Angular code.

Use a Module Loader

Using a module loader like SystemJS, Webpack, or Browserify can simplify the process. Many people claim that this will allow you to follow the same module pattern produced by the TypeScript and will also load files in big applications.

Migrate to TypeScript

As usual, you can begin using TypeScript in our real app. The added benefit is that you can begin learning TypeScript before the real migration process.

Use components directives

I’ve already mentioned that in Angular, everything is divided into components. You can start using this method in your app with the component’s directives. In such a way, you can start decreasing the number of controllers and try to modify the copied code into directives.

2. Understand and Use the Upgrade Adapter

It goes without saying that the upgrade module in Angular will allow you to start using it in your application and with frameworks coinciding at the same time. Another factor to consider is that you can incrementally upgrade elements and services, which can be important if you have a big application that looks like it will take lots of effort to migrate.

3. Upgrade the Components

Components in AngularJS applications must be changed in a certain way for the upgrade module to make them work with Angular. The components directives in AngularJS need to include the following features:

1. Restrict
2. Scope
3. Controllers
4. Transclude 
5. Require

The components of directives do not have to include the following features:

1. compile
2. replace: true
3. priority/terminal
4. Upgrade the Services

It seems to me that Upgrading an AngularJS service to Angular‌ ‌migration  is simple: simply include the AngularJS service into an Angular element as a provider and then upgrade the provider. 

Now, you’ve read a few steps which can help you. And it’s time to read important points.

The Application Upgrade Process

I recommend you to read a few steps that the Angular team supports for upgrading an application to Angular. Here are the lists of them:

1. Connect the Angular and ng-upgrade libraries with your current application.
2. Choose a component that you would like to migrate
3. Select the AngularJS directive’s template to adapt to Angular syntax.
4. Use ng-upgrade to export the directive as an AngularJS component.
5. Choose a service which you would like to migrate. Most services should expect minimal to no change.
6. Configure the service in Angular.
7. Don’t forget to repeat steps 2 and 3 in an order convenient for your application development.
8. Once no more elements need to be changed, drop the top-level AngularJS bootstrap and replace it with Angular bootstrap.

To my mind, it would be very difficult to migrate a large AngularJS application to Angular all at once. Additionally, you have to consider the cost and the effort for the migration, as well as the time your team has to spend making it happen. The better way: a regular migration using the methods I’ve described here. This will help you to clean up your code and begin completing the improvements that became possible by the new Angular features.

Conclusion

So, now it’s high time to conclude everything I was talking about in this topic. I hope that now you have some more clarity on a short guide to angular migration. Maybe this topic is a bit old but still important to discuss and to light up. I decided to highlight the most important facts, which can be helpful for you. And now, let’s remember steps to take for upgrading to Angular. Here are the lists of them:

1. Prepare Your Application
2. Understand and Use the Upgrade Adapter
3. Upgrade the Components
4. Upgrade the Services

I hope with all my heart that you enjoyed this topic and picked a lot of interesting information, which will help in your future. Thanks for your attention, enjoy your life, and stay safe!