Hi there! What’s new? I hope you are very well! For a long time, I have been thinking about a new article for you. and today I have prepared a very interesting topic for you which is called “How To Upgrade from AngularJS to Angular with ngUpgrade.” In my opinion, upgrading an existing AngularJS application to Angular is certainly one of the most interesting topics when it comes to Angular. In this article, I’m going to explore what you can do in order to prepare everything for an upgrade, and, of course, how you can eventually use ngUpgrade to upgrade your Angular application. I reckon that this topic will be notable and helpful.
So, let’s go!
So, before you have started to think about going into the process of upgrading you should ask yourself why you want to do it and if the applications you’ve created so far are actually in a state that they need this upgrade. According to experts’ opinion, there are some very strong reasons why one wants to upgrade and here are just a few of them:
Angular comes with a way faster change. It can be template precompilation, faster bootstrap time, view saving, and plenty of other things that make the framework freakin’ fast.
More powerful Templating
The new template syntax is statically analyzable as presented here, raises many directives, and integrates better with Web Components and other factors.
The next version of Angular has been divided up into two components, an application layer, and a render layer. This allows us to run Angular in other environments than the browser like Web Workers or even servers.
Of course, at the time of writing this article, this is not true. But the Angular ecosystem will eventually be better and more attractive to use in the future.
As you can see, there are certainly more reasons why Angular 2+ is better than AngularJS but keep in mind that you’re reading about the motivation for upgrading here. And now I want to talk about how you can prepare for an actual upgrade.
Changes in Angular
To begin with, in order to upgrade, you need to understand in what ways Angular 2+ is different. Of course, you will read a list of changes that are important when considering about upgrading:
Components are the original building blocks when building importance with Angular. Most everything is a component, even your application itself.
Components communicate via inputs and outputs, if they run in the Browser, these are element features and events. In this article on demystifying, Angular’s Template syntax describes how they work.
- Content Projection
Basically the new transclusion, but more joined with the Web Components model.
- Dependency Injection
Instead of having a single injector for our complete application, in Angular, every component comes with its own injector.
As usual, there is a way more elements in Angular that will change or will be joined to the framework, such as Routing, Forms, the Http layer, and more.
Upgrading using ngUpgrade
If you want to run both frames side-by-side and make elements interoperable, Angular plans to come with a module called ngUpgrade. Following this, the module works as an adapter facade, so you don’t feel that two frameworks are working side-by-side. I recommend you to try out and work with it. All in all, four elements are needed in order to interoperate:
- Dependency Injection – Opening Angular services into Angular 1 components and vice-versa.
- Component Nesting – Angular 1 directives can be used in Angular 2 elements and Angular 2 components can use Angular 1 directives.
- Content Projection – Angular 1 elements transclude Angular 2 components and Angular 2 component project Angular 1 directives.
- Change Detection – Angular 1 range digest and move indicators in Angular 2 are interleaved.
You must remember that with these four things being interoperable, you can already begin upgrading your application’s part with the help of different components. To my way of thinking, routing is another part that can help but is not certainly necessary since you can hold with any Angular 1 routing system while upgrading.
How ngUpgrade Works?
To put it simply, one of the main tools given by ngUpgrade is called the UpgradeModule. Moreover, this is a module that includes services for bootstrapping and operating hybrid applications that help both Angular and AngularJS code. It is clear from these notes that when you use ngUpgrade, what you’re doing is working with both frameworks AngularJS and Angular at the same time. All Angular codes are running in the Angular framework and AngularJS code in the AngularJS framework. Taking everything into account, it must be said that all Angular code is running in the Angular framework and AngularJS code in the AngularJS framework. There is no emulation going on, so you can expect to have all the features and natural behavior of both frameworks. Don’t forget what happens on top of this is that components are managed by one framework and which can interoperate with those from the other framework.
As a rule, this happens in three main sections: Dependency injection, the DOM, and change detection.
- Dependency injection is front and center in both AngularJS and Angular. You can make AngularJS services available for injection to Angular code by upgrading them.
- Components and the DOM, in the DOM of a hybrid ngUpgrade applications are elements and directives from both AngularJS and Angular. These elements communicate with each other by using the input and output bindings of their frameworks, which ngUpgrade bridges together.
- Change Detection when you downgrade an Angular element and then use it from AngularJS, the component’s inputs will be watched using AngularJS change detection.
So, you’ve read some useful facts about how ngUpgrade works. I hope all this information will be useful in future.
Now, guys, it’s high time to conclude all the information I’ve tried to illuminate in this topic – “How to Migrate from AngularJS to Angular with ngUpgrade.” I tried to demonstrate the most important points, which can be helpful for you. To conclude everything up, I’ll give you the list of the reasons why you want to upgrade and here are just a few of them:
- Better Performance
- More powerful Templating
- Server-side Rendering
- Better Ecosystem
I certainly hope that now you have the answer to the question:” How to Upgrade from AngularJS to Angular with ngUpgrade.” I’m really thankful for reading this article. I’m sure that you will find what you seek.