Angular

This is why you should go Angular 9 today

Published Feb 26, 2020

Updated Mar 23, 2020

6 min read

This article was written over 18 months ago and may contain information that is out of date. Some content may be relevant but please refer to the relevant official documentation or available resources for the latest information.

I followed almost all of the events around the Angular 9 release. After reading the Angular 9 cheatsheet, reading the Angular next docs, and watching the official release party, I chose to write this article about why you should start using v9 today.

This isn't just a new release, the Angular Team did way more than that. We finally have Ivy, and from now on, it's the recommended option for view rendering. This was a big challenge for them, having so many changes and improvements could make Angular apps feel different, making it harder for developers to adapt. One of the top priorities was making sure the number of breaking changes were the least possible.

Before diving into Ivy and why it is so cool, we are gonna talk about how easy it is to update your Angular to v9.

Update has never been this easy

The Angular Team did their best to reduce the manual changes you have to do. There were new schematics created for ng update to automate the migrations for you.

In some cases, it's as simple as running ng update @angular/core @angular/cli, and you're done. If you want a more in depth, step by step guide, I recommend you to visit the Update Angular Site or you could also check out this Angular Update Guide by Brian Love.

If you came from AngularJS, you know how hard updates have been until now. I personally got stuck in AngularJS until Angular 5, just because I thought there were too many breaking changes. But now, it feels more approachable.

You'll need Typescript version 3.7.

What's up with Ivy?

Ivy is the new view rendering engine. If you are like me, you may be thinking, Wait, what?

I won't dive into it, but we can probably rephrase the claim above, for clarity, by saying Ivy is a new way to manage the templates and projections. I know that isn't much simpler. Luckily, you don't have to care.

Now, you may be scratching your head. As I said, the Angular Team focused on respecting the way Angular works now. They wanted to do this huge change without us noticing it.

The change is under the hood, and we have the same API. This means that there are no changes for you!

What I can tell you is why they did this incredible number of changes

Smaller bundle.
Better runtime performance.
Template type checking.

Having a smaller bundle is one incredibly valuable to users. We get an improved UX by responding quicker, but not only that, we also get an SEO boost by being able to serve users faster. By this, I don't mean that Ivy comes with something specific to boost your SEO, but smaller bundle helps with that. If you want to take your SEO score to the next level, you'll need to explore other options like SSG with Scully or SSR with Angular Universal.

Even though Ivy changes the way templates are rendered, your old DOM selection queries in your e2e tests won't be affected.

The improved runtime performance is just perfect because now it's possible to have AOT enabled even in dev mode. According to members of the Angular Team, this is one of the best things about this new update. I don't know how many times I've forgotten to build the application with AOT enabled before pushing my code, leading to errors down the pipeline that could've been captured.

In order to enhance runtime performance, a lot of things had to change. All querying decorators like ViewChild, ViewChildren, and so on, had several changes to make them more predictable. The team is currently discussing better ways to query, but again, without us noticing it.

Template Type-checking is a game changer. Now, Angular can help you make the templates type safe. This is a major improvement, because now you can have fewer tests, and rely more on the platform. If you want to enforce this in your project, do this in the tsconfig.json file:

{
  // your options,
  "angularCompilerOptions": {
    // your angular compiler options,
    "fullTemplateTypeCheck": true,
    "strictTemplates": true
  }
}

This way, Angular will tell you if you're breaking any typing inside a template at compilation time. But let's see it in action. If you have a component like this:

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

@Component({
  selector: "app-sample",
  templateUrl: "./sample.component.html",
  styleUrls: ["./sample.component.scss"]
})
export class SampleComponent {
  @Input() number: number;
}

And you use it like this:

<app-sample [number]="'text'"></app-sample>

You'll get this error when compiling the application:

TS2322: Type 'string' is not assignable to type 'number'.

Very cool, right?

Working without NgModules is possible, even when compiling a single component, leading to faster unit tests. The Angular Team didn't remove the NgModules to avoid changing the way Angular currently works. They have no plans of stopping their support of NgModules any time soon, but there’s a chance that components and core building blocks will be preferred over modules.

This even makes it possible to access lazy loaded components in a simpler way. If you want to learn more about this, you definitely have to check out Angular 9: Lazy Loading Components by John Papa.

ViewChild now, by default, has { static: false }. Remember that you use static true if you want to access the ElementRef before change detection occurs (ngOnInit).

There’s a new version of TestBed, with the new compiler, that improved the entire pipeline. Time of execution can be reduced up to 40%. In a future release, we’ll be able to use AOT compiled components for unit testing. If you have already updated, feel free to share your statistics.

A few things were removed. Now you can't use Renderer, and you have to start using Renderer2. Thankfully, the ng update schematic takes care of this. The ngForm element selector has been removed, and now can only be called by using ng-form.

Thinking ahead of time

If you are making heavy use of entryComponents, you won't need to do it anymore thanks to Ivy. In v9, its deprecation was announced. Also, we can forget about TestBed.get, and start using TestBed.inject, which has the same behavior, but is type safe.

Ivy unlocks the possibility of making internationalization way better and easier to do, but it isn't there yet. We'll need to keep waiting for a more robust i18n integration into the Angular platform.

We should be moving from ts-lint to es-lint. Sadly, for the case of very large apps, it tends to be slower. Nevertheless, there are people currently working to make it better and faster.

I heard people saying that zone.js was about to die, but that's simply not true. Though it's not included as a part of the browser standard, we still need zone.js for the change detection.

What can you do to help?

Update today!
Create issues with reproduction
If you can help solve an issue, go ahead and join the discussion

References

Conclusion

The Angular Team put a lot of effort into this update, by not only including Ivy, but by also making the ng update schematic even better and easier to use. Now, it's our chance to help them. Let's start using Angular v9 today! Let's all create issues with reproducible repositories that can dramatically help speed up things.

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The HTML Dialog Element: Enhancing Accessibility and Ease of Use

The HTML Dialog Element: Enhancing Accessibility and Ease of Use Dialogs are a common component added to applications, whether on the web or in native applications. Traditionally there has not been a standard way of implementing these on the web, resulting in many ad-hoc implementations that don’t act consistently across different web applications. Often, commonly expected features are missing from dialogs due to the complexity of implementing them. However, web browsers now offer a standard dialog element. Why use the dialog element? The native dialog element streamlines the implementation of dialogs, modals, and other kinds of non-modal dialogs. It does this by implementing many of the features needed by dialogs for you that are already baked into the browser. This is helpful as it reduces the burden on the developer when making their applications accessible by ensuring that user expectations concerning interaction are met, and it can also potentially simplify the implementation of dialogs in general. Basic usage Adding a dialog using the new tag can be achieved with just a few lines of code. ` However, adding the dialog alone won’t do anything to the page. It will show up only once you call the .showModal() method against it. ` Then if you want to close it you can call the .close() method on the dialog, or press the escape key to close it, just like most other modals work. Also, note how a backdrop appears that darkens the rest of the page and prevents you from interacting with it. Neat! Accessibility and focus management Correctly handling focus is important when making your web applications accessible to all users. Typically you have to move the current focus to the active dialog when showing them, but with the dialog element that’s done for you. By default, the focus will be set on the first focusable element in the dialog. You can optionally change which element receives focus first by setting the autofocus attribute on the element you want the focus to start on, as seen in the previous example where that attribute was added to the close element. Using the .showModal() method to open the dialog also implicitly adds the dialog ARIA role to the dialog element. This helps screen readers understand that a modal has appeared and the screen so it can act accordingly. Adding forms to dialogs Forms can also be added to dialogs, and there’s even a special method value for them. If you add a element with the method set to dialog then the form will have some different behaviors that differ from the standard get and post form methods. First off, no external HTTP request will be made with this new method. What will happen instead is that when the form gets submitted, the returnValue property on the form element will be set to the value of the submit button in the form. So given this example form: ` The form element with the example-form id will have its returnValue set to Submit. In addition to that, the dialog will close immediately after the submit event is done being handled, though not before automatic form validation is done. If this fails then the invalid event will be emitted. You may have already noticed one caveat to all of this. You might not want the form to close automatically when the submit handler is done running. If you perform an asynchronous request with an API or server you may want to wait for a response and show any errors that occur before dismissing the dialog. In this case, you can call event.preventDefault() in the submit event listener like so: ` Once your desired response comes back from the server, you can close it manually by using the .close() method on the dialog. Enhancing the backdrop The backdrop behind the dialog is a mostly translucent gray background by default. However, that backdrop is fully customizable using the ::backdrop pseudo-element. With it, you can set a background-color to any value you want, including gradients, images, etc. You may also want to make clicking the backdrop dismiss the modal, as this is a commonly implemented feature of them. By default, the <dialog> element doesn’t do this for us. There are a couple of changes that we can make to the dialog to get this working. First, an event listener is needed so that we know when the user clicks away from the dialog. ` Alone this event listener looks strange. It appears to dismiss the dialog whenever the dialog is clicked, not the backdrop. That’s the opposite of what we want to do. Unfortunately, you cannot listen for a click event on the backdrop as it is considered to be part of the dialog itself. Adding this event listener by itself will effectively make clicking anywhere on the page dismiss the dialog. To correct for this we need to wrap the contents of the dialog content with another element that will effectively mask the dialog and receive the click instead. A simple element can do! ` Even this isn’t perfect though as the contents of the div may have elements with margins in them that will push the div down, resulting in clicks close to the edges of the dialog to dismiss it. This can be resolved by adding a couple of styles the the wrapping div that will make the margin stay contained within the wrapper element. The dialog element itself also has some default padding that will exacerbate this issue. ` The wrapping div can be made into an inline-block element to contain the margin, and by moving the padding from the parent dialog to the wrapper, clicks made in the padded portions of the dialog will now interact with the wrapper element instead ensuring it won’t be dismissed. Conclusion Using the dialog element offers significant advantages for creating dialogs and modals by simplifying implementation with reasonable default behavior, enhancing accessibility for users that need assistive technologies such as screen readers by using automatic ARIA role assignment, tailored support for form elements, and flexible styling options....

Oct 25, 2024

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Making Seamless Page Transitions with the View Transitions API

Make Seamless Page Transitions using the View Transitions API Traditionally web applications have always had a less polished experience, both functionally and visually speaking, compared to native applications on mobile and other platforms. This has been improving over the years with the introduction of new web APIs and standards. One such new API that bridges that gap is the View Transitions API. What is the View Transitions API? The View Transitions API is a new browser feature that allows developers to more easily create animated transitions between pages and views, similar to how mobile apps have transitions when navigating between pages. Adding view transitions to your application can reduce the cognitive load on your users and make the experience feel less inconsistent. One great thing about view transitions is that they can be used by both SPAs (single-page applications) and MPAs (multi-page applications) alike! Using the View Transitions API for SPAs Let’s see how we can use view transitions ourselves. We will use examples adapted from demos created by the wonderful Jake Archibald and Bramus. There are some alterations to a few of the examples to make them work with the newest version of the View Transitions API, but otherwise, they’re mostly the same. The process of getting view transitions working for SPAs is as simple as calling document.startViewTransition right before starting navigation and replacing your page’s content immediately after that. You need to make this call in your router or in an event listener that triggers your page navigation. The following is an example of how you can hook into page navigation in a vanilla JavaScript application. This example uses the Navigation API if it’s available. As of the time of writing this article only Chromium-based browsers support the Navigation API, but there is a fallback to using a click listener on link elements so that this works with Firefox and Safari. ` If you’re using a framework, then there’s probably a better way to do this specific to that framework than by using this contrived example. For example, if you are implementing usage of this API with a Next application, you may opt for something like next-view-transitions. For this article, we’re going to focus on the way this is done in vanilla JavaScript so that the fundamentals of using the API are understood. Knowing how it’s implemented in vanilla JavaScript should give you enough understanding to implement this in the framework of your choice if there isn’t already a library that does it for you. Now we have a way to know when a navigation is being requested. Using the above utility function we can start the animation and replace our content as follows: ` getMyPageContentSomehow can be any function that returns HTML. How that is implemented will depend on your application and framework of choice. If you want to run these examples on your machine, the demo repository has instructions in its README. In essence, it’s as simple as hosting an HTTP server at the root of the project and visiting localhost. No fancy build system is required! By default, a fade is done that only lasts for a moment. The animation that happens can be configured using CSS with the ::view-transition-group pseudo-element on the element you want to animate, which in our case is the entire page, and we pass in root. ` Given that the animation properties are used, you have much control over what kind of animation to do. You can change the duration and the interpolation, add keyframes and gradients, and even add image masks. You can learn more about the animation properties in CSS on MDN. Using the View Transitions API for MPAs As mentioned, view transitions also work for MPAs with no client-side routing. Setting up view transitions for MPAs is much easier than for SPAs. All you have to do is include the CSS rule on all pages where you want the animations. ` Of course, like how it works with SPAs, you can customize the animations to your heart’s content using the view transition pseudo-elements. Conclusion I hope this article helped you understand the fundamentals of using the View Transitions API. Now that most browsers support it and it’s not too difficult to add it to existing applications, it is a great time to learn how to use it. You can view a full list of examples here (made by Jake Archibald and Bramus) if you want to see how advanced the animations can get. I like the Star Wars ones especially. The README explains how to get all the examples up and running (a total of 43!)....

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One of the things you'll note from the $effect rune is that dependencies don't need to be explicit. Those will be picked from reactive values read synchronously in the body of the effect function. ` Something to bear in mind is that these dependencies are picked each time the effect runs. The values read during the last run become the dependencies of the effect. ` Depending on the result of the random method, foo or bar will stop being a dependency of the effect. You should place them outside the condition so they can trigger reruns of the effect. *Variants* of the effect rune are $effect.pre, which runs before a DOM update, and $effect.tracking(), which checks for the context of the effect (true for an effect inside an effect or in the template). $props This rune replaces the export let keywords used in previous versions to define a component's props. To use the $props syntax, we can consider it to return an object with all the properties a component receives. We can use JavaScript syntax to destructure it or use the rest property if we want to retrieve every property not explicitly destructured.. ` $bindable If you want to mutate a prop so that the change flows back to the parent, you can use the $bindable prop to make it work in both directions. A parent component can pass a value to a child component, and the child component is able to modify it, returning the data back to the parent component. ` $inspect The $inspect rune only works in dev mode and will track dependencies deeply. By default, it will call console.log with the provided argument whenever it detects a change. To change the underlying function, use $inspect.with().with): ` $host The host rune gives access to the host element when compiling as a custom element: ` ` Other changes Another important change is that component events are just props in Svelte 5, so you can destructure them using the $props() rune: ` A special children property can be used to project content into a component instead of using slots. Inside the components, use the [@render[(https://svelte.dev/docs/svelte/@render) tag to place them. ` Optional chaining (?.) prevents from attempting to render it if no children are passed in. If you need to render different components in different places (named slots before Svelte 5, you can pass them as any other prop, and use @render with them. Snippets Snippets allow us to declare markup slices and render them conveniently using the render tag (@render). 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Oct 18, 2024

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Whether it's modernization or custom software solutions, our team of experts can guide you through best practices and how to build scalable, performant software that lasts.

This is why you should go Angular 9 today

Update has never been this easy

What's up with Ivy?

Thinking ahead of time

What can you do to help?

References

Conclusion

You might also like

The HTML Dialog Element: Enhancing Accessibility and Ease of Use

Making Seamless Page Transitions with the View Transitions API

Svelte 5 is Here!

"How do I undo my most recent commit?" - Mastering the git reset command

Let's innovate together!

You might also like

The HTML Dialog Element: Enhancing Accessibility and Ease of Use

Making Seamless Page Transitions with the View Transitions API

Svelte 5 is Here!

"How do I undo my most recent commit?" - Mastering the git reset command