One of the reasons of bad performance is executing your application with lot of modules. For example, we have a web application with 3 modules, on a landing page, all the three modules are executing every time. But at some point, our application starts raising issues of performance because of calling multiple modules at a time. To overcome this problem, we can use this technique of angular 4, lazy loading.
Moreover, we should use it in a way that helps us to load the modules which are needed for the page loading only. As I mentioned above, we can use lazy loading in our app easily by calling the necessary modules on a particular page. To achieve lazy loading in angular 4, we can use the routes because they are playing an important role. This example will have a module lazy will be called lazily using the technique of lazy loading in angular 4.
Learn more about Set up your first Angular 4 App. Learn more about Angular 4 Router Outlet. You can verify that in your browser console, lazy. Full example, Angular 4 Lazy Loading Example. Mohit Tanwani is an enthusiast Techie, a blogger, and IT geek.
He has been crazily involved in the industry for more than 6 years now. Tech Angular 4. By Mohit Tanwani Last updated Jan 30, Share Facebook Twitter Linkedin Email.
This page will guide you over the concept of Lazy Loading in Angular 4. Lazy Loading. Mohit Tanwani. You might also like More from author. Prev Next.
Most reacted comment. Hottest comment thread. Recent comment authors. Notify of. Agree with you, it was just for understanding to the beginners. And welcome to my blog!We will build an Angular lazy loading example app. Lazy loading is the technique were angular loads the modules only when it is needed rather than all at once.
It is also called on-demand loading. The Angular apps get bigger in size as we add more and more features. The Angular Modules help us to manage our app by creating separate modules for each new features.
But, as the app gets bigger in size, slower it loads. That is because of angular loads the entire application upfront. The slow loading app does not leave a good impression on the user. By Loading only a part of the app i. In Angular, the Lazy loading works at the module level. The Individual components cannot be loaded lazily. The Lazy loading works via the Angular Router Module. Note that there is no component defined in the route.
The loadChildren accepts the value as string. The string is split into two sections separated by. The first part is the full path to the module file without the ts extension.
In the example above. When we define an AdminModule to lazy loaded, the angular creates a separate bundle for the entire module. Any Service defined in the Lazy Loaded Modulewill not be loaded until the user navigates to that module. Hence they cannot be used anywhere else in the application. The Angular creates a separate injector for the lazy loaded module. Therefore, any service provided in the lazy loaded module gets its own instance of the service.
Hence create a service in the lazy loaded module, only if it is used inside the lazy loaded Module. Else consider moving it to the AppModule or a special CoreModule.
As you add more and more features those are added to the main. This route instructs the router load the AdminModule from the path. Next, we need to remove the import of AdminModule from the AppModule. If you did not do it, the module will be loaded eagerly. We have removed the parent route admin as it is now moved to the AppRoutingModule.
Since this is a lazy loaded module, the routes we specify will automatically becomes the child route of admin. Now, when you run ng serve command, you will notice the admin-admin.Lazy loading is the process of loading some features of your Angular application only when you navigate to their routes for the first time. This can be useful for increasing your app performance and decreasing the initial size of the bundle transmitted to the user's browser.
In Angular 8, the syntax for lazy-loading modules has changed and it's now more aligned with the standard browser's API. You now need to use the dynamic import syntax to import your module in the loadChildren property of Angular Router routes. It's promise-based and gives you access to the module, from where the module's class can be called. Dynamic import introduces a new function-like form of import that unlocks new capabilities compared to static import.
Angular provides the loadChildren property of a route's path to specify the module that needs to be lazy loaded when it's first navigated to.
In loadChildrenwe use the dynamic import syntax to lazy-load load-at-demand the admin module. Note: The routing module file should be automatically created by the CLI if you opted for automtically adding routing in your project, otherwise you need to create it manually and add the required code for setting up the router.
We create the routes to the various components of our admin module and we include these routes in the admin routing module.
We need to feed the routes to the Angular Router using the forChild method instead of the forRoot module. Note : We could also automatically generate the routing module for the admin module using the --routing switch i.
That's all we need to set up lazy-loaded modules in Angular 8. As a wrap-up, we've seen how to use the loadChildren property of a route in the Angular Router and the standard compliant dynamic import syntax to lazy load an example admin module. According to v8. Let's see a quick example! Sponsored Links. What Is Angular 9 ivy? How to add Bootstrap 4 to my Angular 9 app? How to Install and Use jQuery with Angular 9?In this tutorial, we'll see by example Angular 6 7 routing and lazy loading components using feature modules and the loadChildren method.
Lazy loading modules in Angular 6 allows applications to load modules only when they are needed i. This has many benefits on your Angular 6 application such as the performance and size. To add lazy loading in your Angular 6 application you need to setup routing to use the loadChildren method and add components that you want to lazy-load inside feature modules i. We assume you have Angular CLI 6 installed. Now, you can create a project using the following command:.
Angular Module Loading: Eager, Lazy and Preloading
In the main routing file app-routing. In the feature module, we include the routes with RouterModule's forChild method instead of the forRoot method. In this tutorial, we've seen how to lazy load modules with Angular 6 router using feature modules and the loadChildren method.
Note : This tutorial works with Angular 6 and Angular 7. Now, you can create a project using the following command: ng new angular6project. Sponsored Links. What Is Angular 9 ivy? How to add Bootstrap 4 to my Angular 9 app? How to Install and Use jQuery with Angular 9? Let's stay connected!Routing is a key component of any modern single page application and clearly is a key component of any AngularJS application. Routing gives some semantic separation of concerns for the user via the browser location bar and also determines the modules and components that are displayed to the user.
The downside of single page apps is that we must provide all the code used in the application on the first page load, which can be quite a heavy download. Enter lazy loading, or only loading the modules and components we need when the user navigates to a route.
In this post we will explain why you want to use lazy loading, some of the basics and some more advanced concepts, and finally a code example to get you started. The downside of this improved UX is that we must load all modules and components on the first load and this can take some time.
With lazy loading we only load the required modules on the first load to improve the user experience. Sending less code means the user sees the application sooner, which means happier users. Lazy loading is performed by allowing the router config to provide the module to load on route execution. This of course relies on you splitting your application into modules. Of course, feel free to check out our previous post on creating exportable feature modules in AngularJS 2.
To utilize lazy loading you must split your code into modules you should be doing this already anyway. Simple and one-to-one with our components and routes. To enable lazy loading, we need to update the routing config to indicate that some modules will be loaded on route execution:.
Pre-loading modules allows us to load some of our lazy-loaded modules as the user is using the application. This can greatly improve the UX, but you still have some logical separation of the code into modules… and they are loaded after the initial module has been loaded.
Here we will show a very simple example where we use the provided PreloadAllModules class from Angular:. If you are interested in creating a custom loader, for example one that only pre-loads ContactModule, check out this post on custom pre-loaders from Victor Savkin.
Home is our default route, and will be loaded automatically. List will be lazy loaded when the user requests this link. Here is a link to the example code from this post if you would like to take a look yourself. A lot of AngularJS end users also use Webpack and AOT compiling to create a compressed and trimmed down application, and you can even split your application into some module chunks to further decrease the initial size of your application.
This excellent blog post by Damien Bod will give you some more details on how to make webpack aware of your modules, and even provides a full example on how to update your local code.
Angular 7/6 – How to Implement Lazy Loading for Components Sample Application Example
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Download address for resource required for example: angular.
Lazy loading in Angular 7
Basic usage of angular js1. First, briefly explain the role of lazy loading: As the name implies, laziness means that resources that need to be loaded are not loaded the first time, but are loaded when the page needs to be used, usually to improve the efficiency of loading the first page. Here is a simple example of the basic use of lazy loading: Example function description: Lazy load resource loaded in controller for page call.