Javascript

Why TypeScript is the Most Important Tool in Open-Source with Nick Taylor

Published Sep 27, 2024

Updated Dec 11, 2024

2 min read

In this episode of the Modern Web Podcast, Nick Taylor, Senior Software Engineer at OpenSauce discusses the current state of open source, including the challenges around funding, sustainability, and contributor burnout. Nick shares insights into how open source has impacted his career and highlights the growing importance of tools like TypeScript in the open-source ecosystem.

The panel also discusses the evolution of TypeScript, its widespread adoption, and its role in shaping the modern web development landscape. They explore the nuances between JavaScript and TypeScript, the friction that developers sometimes face when working with types, and how TypeScript has grown into a default tool for many projects.

Chapters

00:00 - Introduction and Co-Host Introductions 00:47 - Guest Introduction: Nick Taylor 01:37 - The Current State of Open Source 02:50 - Funding Challenges in Open Source 03:54 - Open Source Success Stories and Funding Examples 05:35 - Open Source Burnout and Quiet Quitting in Tech 06:43 - Challenges for Open Source Maintainers 07:26 - Motivation and Incentives for Contributing to Open Source 08:35 - Career Benefits of Open Source Contributions 10:11 - Nick’s Journey into Open Source Contributions 12:38 - The Burden of Managing Popular Open Source Projects 14:27 - Hacktoberfest and Low-Quality Contributions 16:14 - Challenges for Beginners Contributing to Open Source 18:01 - The Impact of Hacktoberfest and Mitigating Spam PRs 20:12 - TypeScript's Rise in Popularity 23:16 - Why TypeScript Became Popular in Open Source
25:45 - The Debate Around Static Typing in JavaScript
27:08 - TypeScript vs. JavaScript: Future Considerations 30:21 - The Role of Build Steps in Modern Development Frameworks
33:35 - The Complexity of TypeScript for Different Developer Levels
36:12 - Enum Usage and TypeScript's Type System 38:53 - TypeScript’s Structural Typing and Its Implications
39:47 - Nick’s Contact Information and Closing Remarks

Follow Nick Taylor on Social Media Twitter: https://x.com/nickytonline Linkedin: https://www.linkedin.com/in/nickytonline/ Github: https://github.com/nickytonline

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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!)....

Aug 2, 2024

4 mins

JavaScript

SSR Finally a First-Class Citizen in Angular?

I am sure you've already heard about server-side rendering (SSR). Generally, it's a technique used to deliver the HTML content generated by the server to the client. The client-side JavaScript framework then hydrates that HTML content to provide a fully interactive application. SSR provides numerous benefits if used correctly, including improved initial load times, better content indexing by search engines, and improved performance on lower-tier devices. Driven by the need for faster, more efficient web applications, with the rise in popularity of Node.js and, thus, server-side JavaScript, SSR has become a de facto standard in modern web development frameworks. At first, SSR was being provided as a part of meta-frameworks like Next.js, Nuxt, or Analog.js. Then, React introduced React Server Components, which marked a significant milestone in the way we think about front-end development. We think of front-end frameworks as being effectively full-stack, and a purely SPA approach is falling out of favor. However, I'm willing to bet that if you're a developer focused mostly on Angular, you may not have heard as much about SSR as your React counterparts. For a long time, Angular has been mostly focused on the SPA approach, and while we had Angular Universal or Analog.js, it was not as widely adopted. And that makes sense, given that Angular was widely regarded as best suited for complex, interactive applications, such as SaaS products or internal company tools, where SEO and initial load times were not as critical as they are for consumer-facing applications. Nevertheless, we have been blessed with the so-called Angular Renaissance, which has, among other things, brought SSR to the forefront of Angular development with the @angular/ssr package. Let's look at what Angular SSR is, how it works, and how you can get started. @angular/ssr The @angular/ssr package is not new; it was written from scratch. It's still Angular Universal. However, it's been pulled into the Angular CLI repository, and the appropriate schematics have been added to make it easier to use. What that means is that you can now add SSR to your Angular application with a single command: ` and you can generate a new SSR application with: ` And to make SSR a first-class citizen, the Angular team is planning to make it the default in the next version. But surely, it's not only rebranding and some CLI commands, you may say. And you're right. You may remember that hydration in Angular Universal has not been optimal as it was destructive and required essentially a complete re-render of the application, thus pretty much negating the benefits of SSR. With the introduction of non-destructive hydration in Angular 16 and its stability in Angular 17, the Angular team has taken a significant step forward in making SSR a first-class citizen. How to Make an SSR-capable Angular Application Let's look at how to use Angular SSR in practice by creating a simple SSR app. First, we need to create a new Angular application with SSR support: ` That will generate a few server-specific files: - server.ts, which is an Express server configured to handle Angular SSR requests by default but can also be extended to handle API routes, or anything else that Express can handle. - src/app/app.config.server.ts provides configuration for the server application similar to your app.config.ts, which defines the configuration for your client application. Both export an instance of ApplicationConfig - src/main.server.ts bootstraps the server application in a similar way to what main.ts does for your client app by calling the bootstrapApplication function. You should have an SSR application ready just like that. You can verify that by running ng serve. The terminal output should show you information about the server bundles generated, and you should be able to see the default app when going to http://localhost:4200. Open the Developer Tools and check the console to see that hydration is enabled. You'll see a message with hydration-related stats, such as the number of components and nodes hydrated. Speaking of hydration... Client Hydration If you open the src/app/app.config.ts in your new SSR application, you'll notice one interesting provider: provideClientHydration(). This provider is crucial for enabling hydration - a process that restores the server-side rendered application on the client. Hydration improves application performance by avoiding extra work to re-create DOM nodes. Angular tries to match existing DOM elements to the application's structure at runtime and reuses DOM nodes when possible. This results in a performance improvement measured using Core Web Vitals statistics, such as reducing the Interaction To Next Paint (INP), Largest Contentful Paint (LCP), and Cumulative Layout Shift (CLS). Improving these metrics also positively impacts SEO performance. Without hydration enabled, server-side rendered Angular applications will destroy and re-render the application's DOM, which may result in visible UI flicker, negatively impact Core Web Vitals like LCP, and cause layout shifts. Enabling hydration allows the existing DOM to be reused and prevents flickering. Event Replay and Improved Debugging With Angular 18, event replay, a feature that significantly enhances the SSR experience, came into developer preview. Event replay captures user interactions during the SSR phase and replays them once the application is hydrated. This ensures that user actions, such as adding items to a cart, are not lost during the hydration process, providing a seamless user experience even on slow networks. To enable event replay, you can add withEventReplay to your provideClientHydration call: ` Furthermore, Angular 18 takes another step towards making SSR a first-class citizen by enhancing the debugging experience with Angular DevTools. Now, DevTools include overlays and detailed error breakdowns, empowering developers to visualize and troubleshoot hydration issues directly in the browser. Constraints However, hydration imposes a few constraints on your application that are not present without hydration enabled. Your application must have the same generated DOM structure on both the server and the client. The hydration process expects the DOM tree to have the same structure in both environments, including whitespaces and comment nodes produced during server-side rendering. Direct DOM Manipulation The fact that server and client DOM structures must match means that components that manipulate the DOM using native DOM APIs or use innerHTML or outerHTML will encounter hydration errors. The errors are thrown because Angular is unaware of these changes and cannot resolve them during hydration. Examples include accessing the document, querying for specific elements, and injecting additional nodes using appendChild. Detaching DOM nodes and moving them to other locations will also cause errors. Direct DOM manipulation is generally considered bad practice in Angular, so I recommend refactoring your components to avoid it regardless of hydration. However, in warranted cases where refactoring is not feasible, you can use the ngSkipHydration attribute until a hydration-friendly solution can be implemented. You can use it directly in a template: ` or as a host binding: ` > Note: The ngSkipHydration attribute forces Angular to skip hydrating the entire component and its children. So use this attribute carefully, as, for example, applying it to your root application component would effectively disable hydration for the entire application. Valid HTML Structure Another constraint is that invalid HTML structures in component templates can result in DOM mismatch errors during hydration. Common issues include: - without a - inside a - inside an - inside another Again, if you have an invalid HTML, you should fix this regardless of hydration. If you are unsure about your HTML's validity, you can use the W3 validator to check it. Zoneless apps or custom Zone.js Hydration relies on a signal from Zone.js when it becomes stable. Custom or "noop" Zone.js implementations may thus disrupt the timing of this event, triggering the serialization or cleanup process too early or too late. This configuration is not yet fully supported. While Zoneless is already available in developer preview and we could assume this issue will be resolved when it lands as stable, there is no explicit ETA mentioned in the official roadmap. I18n One of the biggest blockers for adoption of client hydration was the lack of support for internationalization with hydration. By default, Angular 17 skipped hydration for components that used i18n blocks, re-rendering them from scratch. In Angular 18, however, hydration for i18n blocks got into developer preview. To enable hydration for i18n blocks, you can add withI18nSupport to your provideClientHydration call. ` Third-Party Libraries with DOM Manipulation The last thing to consider is third-party libraries that manipulate DOM, such as D3 charts. They could cause DOM mismatch errors when hydration is enabled. You can use the ngSkipHydration attribute to skip hydration for components rendered using these libraries. Conclusion The Angular team has been doing great work to make the framework more modern and competitive, hearing the community feedback and adjusting the roadmap accordingly. And SSR is an excellent example of that. With the introduction of non-destructive hydration in Angular 16 and making it stable in Angular 17, the Angular team has taken a significant step forward in making SSR a first-class citizen in Angular. The @angular/ssr package is now part of the Angular CLI, making adding SSR to your Angular application easier. The Angular team plans to make SSR the default in the next version, further solidifying its position in the Angular ecosystem. However, as with any new feature, there are some constraints and best practices to follow when using SSR with Angular. You should be aware of hydration's limitations and ensure your application is compatible with it. However, if you follow the guidelines provided by the Angular team, you should be able to take advantage of the benefits of SSR without any significant issues....

Jun 26, 2024

8 mins

AngularJavaScriptExpress.js

Introduction to Zod for Data Validation

As web developers, we're often working with data from external sources like APIs we don't control or user inputs submitted to our backends. We can't always rely on this data to take the form we expect, and we can encounter unexpected errors when it deviates from expectations. But with the Zod library, we can define what our data ought to look like and parse the incoming data against those defined schemas. This lets us work with that data confidently, or to quickly throw an error when it isn't correct. Why use Zod? TypeScript is great for letting us define the shape of our data in our code. It helps us write more correct code the first time around by warning us if we are doing something we shouldn't. But TypeScript can't do everything for us. For example, we can define a variable as a string or a number, but we can't say "a string that starts with user_id_ and is 20 characters long" or "an integer between 1 and 5". There are limits to how much TypeScript can narrow down our data for us. Also, TypeScript is a tool for us developers. When we compile our code, our types are not available to the vanilla JavaScript. JavaScript can't validate that the data we actually use in our code matches what we thought we'd get when we wrote our TypeScript types unless you're willing to manually write code to perform those checks. This is where we can reach for a tool like Zod. With Zod, we can write data schemas. These schemas, in the simplest scenarios, look very much like TypeScript types. But we can do more with Zod than we can with TypeScript alone. Zod schemas let us create additional rules for data parsing and validation. A 20-character string that starts with user_id_? It's z.string().startsWith('user_id_').length(20). An integer between 1 and 5 inclusive? It's z.number().int().gte(1).lte(5). Zod's primitives give us many extra functions to be more specific about *exactly* what data we expect. Unlike TypeScript, Zod schemas aren't removed on compilation to JavaScript—we still have access to them! If our app receives some data, we can verify that it matches the expected shape by passing it to your Zod schema's parse function. You'll either get back your data in exactly the shape you defined in your schema, or Zod will give you an error to tell you what was wrong. Zod schemas aren't a replacement for TypeScript; rather, they are an excellent complement. Once we've defined our Zod schema, it's simple to derive a TypeScript type from it and to use that type as we normally would. But when we really need to be sure our data conforms to the schema, we can always parse the data with our schema for that extra confidence. Defining Data Schemas Zod schemas are the variables that define our expectations for the shape of our data, validate those expectations, and transform the data if necessary to match our desired shape. It's easy to start with simple schemas, and to add complexity as required. Zod provides different functions that represent data structures and related validation options, which can be combined to create larger schemas. In many cases, you'll probably be building a schema for a data object with properties of some primitive type. For example, here's a schema that would validate a JavaScript object representing an order for a pizza: ` Zod provides a number of primitives for defining schemas that line up with JavaScript primitives: string, number, bigint, boolean, date, symbol, undefined, and null. It also includes primitives void, any, unknown, and never for additional typing information. In addition to basic primitives, Zod can define object, array, and other native data structure schemas, as well as schemas for data structures not natively part of JavaScript like tuple and enum. The documentation contains considerable detail on the available data structures and how to use them. Parsing and Validating Data with Schemas With Zod schemas, you're not only telling your program what data should look like; you're also creating the tools to easily verify that the incoming data matches the schema definitions. This is where Zod really shines, as it greatly simplifies the process of validating data like user inputs or third party API responses. Let's say you're writing a website form to register new users. At a minimum, you'll need to make sure the new user's email address is a valid email address. For a password, we'll ask for something at least 8 characters long and including one letter, one number, and one special character. (Yes, this is not really the best way to write strong passwords; but for the sake of showing off how Zod works, we're going with it.) We'll also ask the user to confirm their password by typing it twice. First, let's create a Zod schema to model these inputs: ` So far, this schema is pretty basic. It's only making sure that whatever the user types as an email is an email, and it's checking that the password is at least 8 characters long. But it is *not* checking if password and confirmPassword match, nor checking for the complexity requirements. Let's enhance our schema to fix that! ` By adding refine with a custom validation function, we have been able to verify that the passwords match. If they don't, parsing will give us an error to let us know that the data was invalid. We can also chain refine functions to add checks for our password complexity rules: ` Here we've chained multiple refine functions. You could alternatively use superRefine, which gives you even more fine grained control. Now that we've built out our schema and added refinements for extra validation, we can parse some user inputs. Let's see two test cases: one that's bound to fail, and one that will succeed. ` There are two main ways we can use our schema to validate our data: parse and safeParse. The main difference is that parse will throw an error if validation fails, while safeParse will return an object with a success property of either true or false, and either a data property with your parsed data or an error property with the details of a ZodError explaining why the parsing failed. In the case of our example data, userInput2 will parse just fine and return the data for you to use. But userInput1 will create a ZodError listing all of the ways it has failed validation. ` ` We can use these error messages to communicate to the user how they need to fix their form inputs if validation fails. Each error in the list describes the validation failure and gives us a human readable message to go with it. You'll notice that the validation errors for checking for a valid email and for checking password length have a lot of details, but we've got three items at the end of the error list that don't really tell us anything useful: just a custom error of Invalid input. The first is from our refine checking if the passwords match, and the second two are from our refine functions checking for password complexity (numbers and special characters). Let's modify our refine functions so that these errors are useful! We'll add our own error parameters to customize the message we get back and the path to the data that failed validation. ` Now, our error messages from failures in refine are informative! You can figure out which form fields aren't validating from the path, and then display the messages next to form fields to let the user know how to remedy the error. ` By giving our refine checks a custom path and message, we can make better use of the returned errors. In this case, we can highlight specific problem form fields for the user and give them the message about what is wrong. Integrating with TypeScript Integrating Zod with TypeScript is very easy. Using z.infer<typeof YourSchema> will allow you to avoid writing extra TypeScript types that merely reflect the intent of your Zod schemas. You can create a type from any Zod schema like so: ` Using a TypeScript type derived from a Zod schema does *not* give you any extra level of data validation at the type level beyond what TypeScript is capable of. If you create a type from z.string.min(3).max(20), the TypeScript type will still just be string. And when compiled to JavaScript, even that will be gone! That's why you still need to use parse/safeParse on incoming data to validate it before proceeding as if it really does match your requirements. A common pattern with inferring types from Zod schemas is to use the same name for both. Because the schema is a variable, there's no name conflict if the type uses the same name. However, I find that this can lead to confusing situations when trying to import one or the other—my personal preference is to name the Zod schema with Schema at the end to make it clear which is which. Conclusion Zod is an excellent tool for easily and confidently asserting that the data you're working with is exactly the sort of data you were expecting. It gives us the ability to assert at runtime that we've got what we wanted, and allows us to then craft strategies to handle what happens if that data is wrong. Combined with the ability to infer TypeScript types from Zod schemas, it lets us write and run more reliable code with greater confidence....

Nov 15, 2024

7 mins

JavaScriptZod

Understanding the Difference Between `:focus` and `:focus-visible` in CSS

Understanding the Difference Between :focus and :focus-visible in CSS I have learned my fair share about the importance of keyboard accessibility, so I know that visual indication of the focused element is very important. But the well-known :focus pseudo-class is not always the best fit for this job. That's where :focus-visible comes in. Let's look at the differences between these two pseudo-classes and explore the best practices for using them effectively. What is the :focus Pseudo-Class? The :focus pseudo-class is a CSS selector that applies styles to any element that receives focus, regardless of how that focus was triggered. This includes focus events from keyboard navigation, mouse clicks, and touch interactions. Example Usage of :focus ` In this example, the button will display a blue outline whenever it is focused, whether the user clicks on it with a mouse, taps it on a touchscreen, or navigates to it using the keyboard. What is the :focus-visible Pseudo-Class? The :focus-visible pseudo-class is more specialized. It only applies styles to an element when the browser determines that the focus should be visible. This typically occurs when the user navigates via the keyboard or assistive technologies rather than through mouse or touch input. Example Usage of :focus-visible ` Here, the button will only show a blue outline when focused through keyboard navigation or another input method that usually requires visible focus indicators. Key Differences Between :focus and :focus-visible :focus - Behavior: Applies to any element that receives focus, regardless of the input method. - Use Cases: Ensures that all interactions with the element are visually indicated, whether by mouse, keyboard, or touch. :focus-visible - Behavior: Applies styles only when the focus should be visible, such as using a keyboard or assistive technology. - Use Cases: Ideal for scenarios where you want to provide focus indicators only to keyboard and assistive technology users while avoiding unnecessary outlines for mouse and touch users, typically required by design. Accessibility Implications :focus - Pros: - Guarantees that all users can see when an element is focused, which is critical for accessibility. - Cons: - Can lead to a suboptimal experience for mouse users, as focus styles may appear unnecessarily during mouse interactions. :focus-visible - Pros: - Enhances user experience by showing focus indicators only when necessary, thus keeping the interface clean for mouse and touch users. - Tailors the experience for keyboard and assistive technology users, providing them with clear visual cues. - Cons: - Additional considerations may be required to ensure that focus indicators are not accidentally omitted, especially in older browsers that do not support :focus-visible. - There may be cases where you want to show focus indicators for all users, regardless of input method. Best Practices for Using :focus and :focus-visible To achieve the best accessibility and user experience, combining both :focus and :focus-visible in your CSS is often a good idea. Combining :focus and :focus-visible ` Here is a Stackblitz example of what such styling could look like for you to try out and play with. Additional Tips - Test with Keyboard and Assistive Technology: Ensure that your web application is navigable using a keyboard (Tab, Shift + Tab, etc.) and that focus indicators are visible for those who rely on them. It's never a bad idea to include accessibility testing in your e2e testing suite. - Provide Clear Focus Indicators: Make sure that focus indicators are prominent and easy to see. A subtle or hard-to-spot focus indicator can severely impact accessibility for users who rely on keyboard navigation. Conclusion The :focus-visible pseudo-class offers a more refined way to manage focus indicators, improving accessibility and user experience, particularly for keyboard and assistive technology users. By understanding the differences between :focus and :focus-visible, and applying best practices in your CSS, you can create more accessible and user-friendly web applications. Remember, accessibility should never be an afterthought. By thoughtfully applying focus styles, you ensure that all users, regardless of how they interact with your site, can easily navigate and interact....

Nov 8, 2024

3 mins

AccessibilityCSSPlaywright

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Why TypeScript is the Most Important Tool in Open-Source with Nick Taylor

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Making Seamless Page Transitions with the View Transitions API

SSR Finally a First-Class Citizen in Angular?

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Understanding the Difference Between `:focus` and `:focus-visible` in CSS