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Progressive Web Apps and Mobile Apps


In a talk by Alex Russell titled, "The Mobile Web: MIA", Alex discussed a number of issues facing the expansion of the web platform on mobile devices. He noted that, "People don't use the web the way they lean on it, and rely on it, and come to depend on it on desktop." In his talk, he noted that people use the web about 4% of the time they are using phones, and dropping. The rest of the time, users are typically interacting with mobile apps, rather than the browser.

Much of this is driven by the fact that companies that own the platforms (Google and Apple, in particular) are primarily focused on native app developments. This focus on mobile app development pushes the market to accept the importance of a mobile app, and drive users to leave the web for a native experience. Mobile app development locks experiences to devices and operating systems, which increases the cost of development. Users, in turn, grow to expect mobile applications, even for simple tasks such as viewing bus routes or filling out a form.

As web developers, we know there is another option for app development. Progressive Web Apps (PWAs) are built with standard web technologies - HTML, CSS, JavaScript, and modern browser APIs - to provide an enhanced experience when using them on supported platforms. By utilizing the latest browser features, web developers can construct the same experiences users expect of native applications. These features include: accessing the camera, notifications, Bluetooth and network information- even augmented/virtual reality and payments. Browsers have been working to support these features for years, and some companies (such as Twitter) have been building PWAs to provide an improved experience for their platforms.

Let's say that we have a company, BetterX, which is looking to build a new app for their users. The primary goal is to provide an excellent experience for mobile users, including offline support and hardware features such as notifications and payments. We will explore and compare the benefits of native mobile applications and PWAs, and discuss why each platform may be the better choice.

Progressive Web Apps - The Open Web

One of the key benefits when considering a progressive web app is that we are utilizing modern web development tools to build our application. As web developers, we are already familiar with a number of complex tasks, such as state management, caching, and performance optimization. To build a PWA, we need to take these concepts to their natural conclusions. By utilizing a service worker to cache assets and IndexedDB or other methods to store local data, we can build a system that is capable of working fully offline. By using network detection, our application can determine whether an internet connection is available, and provide that information to the user.

Another benefit of building with web technologies is that we have a better chance of achieving the goal of, "write once, run anywhere". By utilizing standard architecture patterns in our application, and relying on progressive enhancement as the browser/platform we are running on allows, our PWA can run on both mobile devices (as an installed app) or on browsers. Most developers are already familiar with responsive design, which allows a website to change its appearance depending on the viewport or device. The same concepts can be applied to a PWA, incrementing our functionality as the device allows it, and providing a fallback for when certain features are not available.

Web development also has the benefit of traditionally being cheaper than mobile app development. Smaller companies don't always have the time or money to invest in a mobile development team. Most of them, however, do have a website. By utilizing some of the APIs available to progressive web applications, these shops and companies can provide a mobile experience. Also, if a website/web app is built with mobile devices in mind, the time it takes to build a fully functional PWA could be weeks, compared to a brand new mobile application taking months.

PWAs can also be significantly smaller than their native alternatives. In a report by Google, the Twitter PWA "requires less than 3% of the device storage space compared to Twitter for Android". As fewer mobile devices have ports for expanded storage space, the size of applications becomes increasingly more important.


However, there are some drawbacks to choosing a progressive web app. Users expect to find mobile applications in the app store, not on a website. In his talk, Alex Russell shares a screen of an Android device with a Google search bar at the time, and a row of icons at the bottom, including the Google Play Store. He explains that people click on the search bar when they are looking for "answers", and click on the store when they are looking for "experiences". For PWAs, the way to install them is to visit the URL, and click on the install button when prompted. This is not how users have been trained to find apps for their smartphones.

It's also not clear to a user what installing a PWA achieves. On an Android device where a user installs a PWA, an icon for that app appears on their desktop as any other app would. However, depending on the app, this could be a complete experience, including offline support, or it could simply be a wrapper to load a website. In many cases, a PWA is little more than an enhanced bookmark on a mobile phone.

Mobile Applications - Platform Builders

Mobile apps are the standard established by Google and Apple for delivering user experiences on phones and tablets. Apps are an expected feature of any new platform - it's rare to see a new service thrive without a presence in the Google Play Store, or Apple App Store. Keystone applications, like Facebook or Twitter, are regularly highlighted by these platforms as a way to bring new users into their walled gardens.

Users are trained to search for, and install, mobile applications. Often, websites will guide users directly to the respective app store. On iPhones and iPads, the app store is the only way for apps to be installed on a phone, making the store even more crucial to a product's success on the platform. Since Apple does not support PWAs in Safari, this makes mobile development a requirement to reach customers within their ecosystems.

Mobile development has first-class support from both Apple and Google, providing access to APIs and features as new hardware is released. Apps being developed for newer devices can do more, and utilize more resources than ever before. Resource-intensive apps like Adobe Photoshop or Procreate can leverage these resources to achieve results previously held only on desktops and laptops.

Modern mobile development frameworks, such as Flutter and React Native, allow developers to target these devices in a cross-platform way. They provide access to the APIs and features of the hardware, and a streamlined way to write a majority of your app once, while targeting multiple platforms. Other frameworks such as Cordova or Capacitor even allow for using modern web technologies, and having a fully bundled app that can be released on the app store.


Mobile development provides amazing functionality and allows for powerful applications to be built. However, it comes at a cost. These applications can only run on the latest and greatest hardware and OS version. Most mobile users do not have access to the hardware we, as developers, are using to build our applications. What takes a few seconds to load on 5G using an iPhone 12 Max could take nearly a minute to load on phones common in most of the world. Also, final application sizes are going to impact how many users can actually download our app in the first place.

In many cases, a mobile application in the app store could become more of a burden than a benefit. Consider that you're visiting a foreign country. Because you are roaming, your internet speed is significantly slower than you are used to. While traveling in a city, you want to check for bus routes and schedules. You go to the website for the municipal bus system, and are directed to download an app to view schedules. This app is not too large (my local bus system's app is 8.6 MB), but on your slower connection still takes a long time to download. Also, you may only need this app once or twice, before you travel to your next destination. A website (or PWA) would provide a much smoother experience than requiring a mobile app be downloaded.


Regardless of which architecture you decide to use for building out your mobile application, there are some considerations to keep in mind. First, your developers are going to have better hardware and internet connection than many of your users. Most users do not have a high-end iPhone or Android device, and are not on 5G or gigabit internet. Whether you're building a PWA or a native app, remember that every megabyte will take substantially longer to download and initialize, and your application will run slower. If able, you should test your applications on slower or ittermitant internet speeds, or on lower end hardware.

In general, if you are going to build a mobile application, it has to be lean, loadable, and support offline use. Many companies, (and some end users), will try to push for new features or content without regard for the experience of all users. Setting up a truly performant and offline-friendly experience is complicated, but it truly is worth taking into account all potential users as you work to build and deploy it.

If you decide that building a progressive web app is the way to go for your app or company, it is important to remember that PWAs are not supported in Safari or on iOS/iPadOS. On both iPhones and iPads, the only browser engine is WebKit, regardless of which browser you are using. This means that users will not be able to install your PWA on Apple mobile devices, and the browser APIs may not be available. Take this into account while building your app, and allow for graceful degredation when features are not available. This is not to say that you shouldn't build a PWA if you want to target Apple's ecosystem - much the opposite! The more PWAs that exist, and have a large number of users on Apple's devices, the better chance that Apple will support the standardized browser features that enable PWAs.

At the end of the day, choose the architecture that best supports your users, and build with them in mind. Your app should help your users and customers in some way, and should not be a burden to them. It may be fun to try out a new mobile framework, or build a PWA with enhanced features, but not if it does not serve the end user.

This Dot Labs is a development consultancy that is trusted by top industry companies, including Stripe, Xero, Wikimedia, Docusign, and Twilio. This Dot takes a hands-on approach by providing tailored development strategies to help you approach your most pressing challenges with clarity and confidence. Whether it's bridging the gap between business and technology or modernizing legacy systems, you’ll find a breadth of experience and knowledge you need. Check out how This Dot Labs can empower your tech journey.

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Remix Deployment with Architecture cover image

Remix Deployment with Architecture

Intro Today’s article, will give a brief overview of the Architect framework and how to deploy a Remix app. I’ll cover a few different topics, such as what Architect is, why it’s good to use, and the issues I ran into while using it. It is a straightforward process, and I recommend using it with the Grunge Stack offered by Remix. So let’s jump on in and start talking about Architect. Prerequisites There are a few prerequisites and also some basic understandings that are expected going into this. The first is to have a GitHub account, then an AWS account, and finally some basic understanding of how to deploy. I also recommend checking out the *Grunge Stack*__ here if you run into any issues when we progress further. What is Architect? First off, Architect is a simple framework for Functional Web Apps (FWAs) on AWS. Now you might be wondering, "why Architect?" It offers the best developer experience, works locally, has infrastructure as code, is secured to the least privilege by default, and is open-source. Architect prioritizes speed, smart configurable defaults, and flexible infrastructure. It also allows users to test things and debug locally. It defines a high-level manifest, and turns a complex cloud infrastructure into a build artifact. It complies the manifest into AWS CloudFormation and deploys it. Since it’s open-source, Architect prioritizes a regular release schedule, and backwards compatibility. Remix deployment Deploying Remix with Architect is rather straightforward, and I recommend using the Grunge Stack to do it. First, we’re going to head on over to the terminal and run __npx create-remix --template remix-run/grunge-stack__*. That will get you a Remix template with almost everything you need. *Generating remix template*__ For the next couple of steps, you need to add your AWS_ACCESS_KEY_ID__ and __AWS_SECRET_ACCESS_KEY__ to your repo’s secrets. You’ll need to create the secrets on your AWS account, and then add them to your repo. *AWS secrets*__ *GitHub secrets*__ The last steps before deploying include giving CloudFormation a SESSION_SECRET__ of its own for both staging and production environments. Then you need to add an __ARC_APP_SECRET__. *Adding env variables*__ `bash npx arc env --add --env staging ARCAPP_SECRET $(openssl rand -hex 32) npx arc env --add --env staging SESSIONSECRET $(openssl rand -hex 32) npx arc env --add --env production ARCAPP_SECRET $(openssl rand -hex 32) npx arc env --add --env production SESSIONSECRET $(openssl rand -hex 32) ` With all of that out of the way, you need to run __npx arc deploy__*, which will deploy your build to the staging environment. You could also do *__npx arc deploy —-dry-run__* beforehand to verify everything is fine. Issues I Had in My Own Project Now let's cover some issues I had, and my solution for my own project. So, I had a project far into development, and while looking at the Grunge Stack, I was scratching my head, trying to figure out what was necessary to bring over to my existing project. I had several instances of trial and error as I plugged in the Architect related items. For instance: the arc file, which has the app name, HTTP routes, static assets for S3 buckets, and the AWS configuration. I also had to change things like the *remix.config*__ file, adding a *__server.ts__* file, and adding Architect related dependencies in the package.json. During this process, I would get errors about missing files or missing certain function dirs(), and I dumped a good chunk of time into it. So while continuing to get those errors, I concluded that I would follow the Grunge Stack, and their instructions for a new project. Then I would merge my old project with the new project; and that resolved my issues. While not the best way, it did get me going, and did not waste any more time. That resolved my immediate issues of trying to get my Remix app deployed to AWS, but then I had to figure out what got pushed. That was easy, since it created a lambda, API gateway, and bucket based on the items in my arc file. Then I realized, while testing it out live, that my environmental variables hadn’t carried over, so I had to tweak those on AWS. My project also used a GitHub OAuth app. So that needed to be tweaked with the new URL. Then it was up and running. Conclusion Today’s article covered a brief overview of what Architect is, why it’s good to use, how to deploy a Remix app and the issues you might have. I hope it was useful and will give others a good starting point....

Leveling Up Your Work Through Architecture Design and Time Estimation cover image

Leveling Up Your Work Through Architecture Design and Time Estimation

> This post can be useful for developers at any level! However, it is written mostly for entry-level developers who are starting to transition into a more intermediate role. You’re rocking your first development job. You’re completing tasks, the team loves you, you still have tons of questions but you can get answers and build what you’re asked to build. But you want to keep improving your skills and giving yourself more options. Some of that skill can only come from actually building things over time. But surely there’s something you can do to level up besides that, right? There is! One way to help deepen your understanding of the software you’re writing and make yourself look more impressive is by improving your ability to estimate your time, and how you talk about your work. That’s what we’re going to dig into today! Some terminology You might have heard of, or have read terms like “software architecture” and “quality attributes” and, upon trying to look into them, been met with a LOT of jargon and dense terminology. So before we get too far into this, let’s go over a few terms we’ll use. (This is by no means meant to be a complete description of these terms. The aim is to be clear enough to continue our discussion here, and let you get started.) - Software architecture:__ This term means how your system is organized. It’s like the blueprint for the application or website you’re building. How do all the pieces we build fit together and interact with each other? What’s the main goal we’re trying to achieve with this codebase? That’s what this term is talking about. - Software design:__ Once we have the blueprint, we need to figure out how to build the pieces to make that structure come to life. This is where the design comes in. It’s more code-specific and focuses more on the specifics of what we need to build and how. What languages are we using? How do we get this component to be interactive or usable like we want? This is all the design. - Software quality attributes:__ Sometimes referred to as “ilities” because a lot of them end with those letters, these are words we use to describe the software we write. Common ones would be accessibility, reliability, or performance. These are words used to describe some of the key qualities we want our software to have. You can start with this list of quality attributes or do a search for “software quality attributes”, and find all sorts of articles covering a lot of the common ones. - Time estimation:__ This is the skill of being able to consider a task and estimate how long it would take you to complete the task. Time can be a funny thing, and it’s pretty common to think something will be easy and have it take way longer, or think something will be complex, and it turns out to be straightforward. - Trade-offs:__ This is the idea that two things can’t be equally balanced and/or important. There’s a joke about how people want things fast, cheap, and good and you can’t have all three. This is the same idea. Very often, by increasing one quality, you have to decrease another. The balance of those, and the choice to focus on one quality more than another, is called a trade-off. You’re trading the strength of one quality for another. When we’re using the phrase “architecture design” in this article, we’re combining all these concepts together. How do we get started? Ok, so we’ve got some terms now. But what do we do with them? How do we get better at designing software, and estimating our time? I’ve got two templates to share with you that can help you start to develop these skills. Both will involve writing, but I’ve tried to make them as straightforward to fill out as possible so it’s not a chore to use them. I’ll share links for the templates later on. But first, we’ll go over the actual contents of both of them and talk about how to use them. These templates can be useful for any task, no matter how complex. However, super simple tasks like fixing a broken link on a page, or adjusting a color value to improve its contrast may not be the best choice for it. It is useful to use this template on a task that you fully understand, so you get some practice with thinking about the tradeoffs you’re making, and get used to some of the terminology and how to talk about the software you build. But this can really help when you start getting larger tasks or features- ones that might contain multiple parts working together or some complex logic to get the task working properly. The architecture design template For this template, the goal is to complete this first before you do any work on your task. Use this as a tool to help you think through your work before you get started on it so you can have a better understanding of what the task is asking of you, and let you start thinking about the attributes you’re building for. There are 7 sections for this document, each with a title and description. Let’s go over each piece to see how they work. Big picture: What’s the ask? What’s the ticket/task trying to solve? What’s the end goal of this body of work? Describe the problem in the most ELI5 way you can.* Use this section to describe the task you’re working on. Act like you’re talking to someone with very little understanding of the situation, like a project manager on another team or to a friend of yours that doesn’t work with you. This section helps you make sure you have a strong handle on the work you’re being asked to do, and what the end result should be. Requirements Is there acceptance criteria? A specific way it needs to work? What makes this ticket / task count as complete? Steps to reproduce and/or screenshots are helpful here too, if available.* Some of this can often be copied over from the ticket you’re working on. Make note of how you can tell that this task is complete, and any specifics that you need to make sure work as expected when you’re ready to have someone review it. Constraints Are there specific things you can / can’t use? Something you have to make sure doesn’t break? Tools you have to use because of where you have to work in the codebase?* Making note of constraints can be super helpful. Maybe you have to use a specific UI library to complete this because the rest of the project uses it. Or perhaps this task has been attempted before, and you don’t want to repeat a version that didn’t work. Getting used to thinking about the constraints you’re working within can help prep your brain to think around these concepts. Architecture and Tradeoffs Where does this code live? (login, ui, db, etc) What software quality attributes are we focused on for this task? List out the primary and secondary attributes (maybe a third if it feels necessary).* In this section, we’re focusing on developing our architecture and design skills in detail. Talk a little about how the codebase is structured, and where the work for this task will be located. Also, pick one or two software quality attributes that you think fit this task. Does the work you’re doing help improve the site’s overall accessibility? Does it make the application more reliable for end users? Does it help to keep our codebase’s maintainability within a reasonable level? Use one of the lists above or your own searches to build out a list of the attributes you might build for regularly, and pick out one or two of them that relate the most to this task. Then, talk a little about why you picked those traits and your thoughts about why they’re applicable. Being able to explain your reasoning here will both help you gain more understanding of the work you’re doing, and the words you’re using to describe it, and give whoever reads this document a better glimpse into the work you do and how you think about it! Initial Gameplan Considering all the above, what seems like the path forward? What are the steps for how you think it can be solved/completed? Where are you starting?* Now that you’ve spent a little time thinking through the task, and some of the things you should remember about it (like how it’s structured, the tools you have to use, and what’s important to keep in mind while you’re solving it) - write out the steps you think you should take to accomplish the task. It’s perfectly okay to not fully follow this plan as you start to build! We can never fully predict everything that might happen as we start to work in a codebase. The goal here is to give yourself a solid place to start, with all the details we’ve listed fresh in your mind. Process Notes As you solve this - keep this area updated with rough notes. What did you try that didn’t work? Why not? If you have to pivot, what did you switch to and why? Maybe something worked but you still pivoted - what tradeoffs were made, and what’s the reasoning behind it?* As the description implies, this space is all for you. Try to keep notes as you go. If you do have to change course from your game plan, why and what did you change? Did you find another problem you didn’t even know existed? Or maybe you were able to try a new concept out and it worked! Celebrate your process here. None of this needs to be in complete sentences or easy for anyone but you to understand. This space is all yours to help you keep thinking through the work as you’re doing it! Final Solution You did it! Form a narrative. Now that you’ve got the issue solved, what does it look like? How did you do it? What did you learn along the way? Is the final solution the same as what you thought, or did the ask pivot along the way? Share screenshots if available.* The final wrap-up! Try to write this similarly to how you started with the big picture. Did your initial plan end up working, and if not why? Were there any interesting plot twists throughout the process? Share the wins, the struggles, and the end result here. Screenshots can be perfect here to see a visual of your work! I also typically leave a little space at the bottom to wrap up any lessons I learned for myself, and leave a little room to talk about my time estimate and reasonings behind how it turned out the way it did. But those are completely optional. --- Because I use a Notion database to help me keep track of these documents, I also have a few properties I can fill out related to the project this document is for, what my time estimate and result were, and the quality attributes I selected. Having those visible at a glance is super helpful for me. The biggest thing I’d recommend to track with this is the date you filled it out. Having that date to help you organize and find your documents is super helpful as your collection grows. I typically title mine based on the project it’s for and the name of the task, but you can name yours whatever you’d like! Now let’s talk about how to track our time for this task. The time estimate template This one is a lot less detailed, but just as important! Being able to improve your knowledge of how long different tasks take you will be a super handy skill as your career continues. The main idea with this template is to keep track of two sections: how long you think something will take you (the estimate), and how long it truly takes you. Our goal is to get those two sections to be as close to the same number as possible. Remember that our goal here is NOT perfection. That’s impossible to reach.__ Our goal is simply to get them to be close to each other. Most people (even managers) understand that an estimate is not a guarantee. But the closer you can get your estimates to the true time it takes you, the more reliable you seem and the more accurately your team can make progress. There are three main sections to this template. The actual numbers Most importantly, we want an estimated total time and an actual total time, as well as a calculation of the difference between those two numbers. Is our estimate higher, or is the actual total time higher? That difference is what we’re trying to keep as close to zero as possible. I like to break my time tracking down into categories, so I can also see if particular parts of my work take me longer (or shorter) than I think. For each of these, I do the same thing: make an estimate, and record the actual value. The categories I like to track are: Investigation:__ time to fill out my architecture design, do a little looking into the task, make sure I understand fully what I’m being asked to do, and that I have all the information I need to complete it. Coding:__ time to do the actual work. Most of my time calculation goes into this category. Testing:__ I use this for either writing actual unit or end-to-end tests, or for manual testing. This is where I double-check to make sure I didn’t break anything or track time spent on that one last piece of functionality that doesn’t quite work right. Review:__ any feedback I get on my Pull Requests or code reviews that require me to make changes go into this category. Space to record the numbers as I go The Pomodoro technique works really well for me with time tracking, though I change up my “working time” numbers to make them easier for me to calculate. I’ve found the most straight forward way for me to do this is to have a title for each section of time that I’m tracking, with space underneath each one. Then, I have a legend of colored dot emojis related to a different amount of time: 15 minutes, 30 minutes, and 60 minutes. Then, as I do my rounds of working time, each time I’m done with a round, I select the right colored dot for the amount of time I did, copy it, and paste it under the section the work I did belongs to. Keep repeating this until the work is complete! Once your task is done, all you need to do is count your dots, and record the total number they represent in your actual time section from above. Here’s a screenshot of what one of my completed sections look like, so you can better see what I mean. From this tracking section, I can quickly see that I spent 15 minutes on both testing and review, and an hour and 45 minutes on coding. If I don’t happen to spend any time on a section (in this instance, I’d done some investigating in a separate ticket, so I already knew the work that needed to be done), I just leave it blank. I have a section at the top of my page for tracking the total number for each category. So I use this area to keep track as I’m doing small rounds of work. Then, when I’m done, I add up each number and put it in the section at the top of the page for that category. Notes I also have a section for notes at the bottom of my document. I keep this area for anything relating to my time tracking. Did something break unexpectedly, causing my estimate to be off? Did I not need a section for some reason? Or did something work way better than I thought it would? Those are the kinds of things worth keeping notes of here. Can you tell why your estimate and actual times were off? Sometimes we simply don’t know, but being able to keep notes on the things we can realize as we’re doing them helps us get better the next time! Tying these together and talking about it with others You can use both of these templates together or on their own, and you’ll gain a great amount of knowledge about your skill level and your growth over time from them! But they can also really shine using them together. While these are great tools for your own personal knowledge and growth, I also highly recommend sharing them with someone else. It’s a great idea to set a goal to be better with estimating your time, and sharing that goal with your manager. Then, you can use the time estimation template to build up some estimates, and share those with your manager. Maybe you have a senior developer on your team that you really respect, and you’d like to get their opinion on the task you’re working on. If you’ve filled out the architecture design for that task, you can share it with them and have a conversation about it. They can potentially provide you with things to consider for your next task, or get you thinking more deeply about the quality attributes you selected, and why they may or may not have been the best fit for your work. The design documents are also great to share with your manager! It’s a great way to show that you’re starting to think about your work on a deeper level and starting to consider the quality and complexity of your work. It can also be helpful reference material for them when promotions and new work becomes available. They’re more likely to think you might be a good pick for the next big thing if you’re already showing them you’re starting to think about things at a higher level! The Notion template links The links for both of these documents as Notion templates are below. Please feel free to duplicate a copy for yourself if you like using Notion, or just take a peek at them to see the actual layout of them and adapt that for whatever tool works best for you. These documents are set up to be used within a Notion database. We won’t cover that in detail here, but the Notion documentation should be able to take care of those details for you (and we have a link to get you started below as well). In general, you can create a database within Notion, and then set a template to use for each new entry. That way, when you go to create a new item, it will automatically pull up these templates for you, so you don’t have to copy and paste them every time! And the fields at the top will be visible when you go to look at your database, which makes it a little nicer to get a quick overview of your documents and the progress you’re making. Now go forth and deepen your knowledge! - Time estimation template - Architecture design template - Notion database templates documentation...

Styling Vue Single-File Components cover image

Styling Vue Single-File Components

Introduction If you have any experience with writing Vue single-file components, you have probably spent some time writing CSS within your component. Single-File Components allow developers to group code together in more logical ways, rather than breaking up components by language utilized (HTML, CSS, or JavaScript). Being able to group component styles directly next to the HTML that it applies to is one of the major benefits of Vue, including the ability to scope CSS to the component so that it doesn't affect other parts of the UI. However, there are a number of features to Vue's CSS integration that you may not be familar with, such as applying styles directly to slotted elements, or the newest features available in Vue 3.2. Let's explore some of these other ways of styling Vue single-file components, and how they can benefit your applications. Scoped Styles Let's start with the most common usage of CSS in Vue: scoped styles. One of the difficulties on writing modern applications is that our CSS files begin to grow larger and larger, until nobody really knows where certain styles are used or what a given change might affect. This can lead to copying certain CSS selectors, and simply duplicating them for each component. There are other solutions for this (such as BEM or utility classes), but when working with a component-based framework like Vue, it makes a lot of sense to group CSS classes within the component. Scoped styles allows us to write CSS that only applies to the component we are working in. Here's an example from the Vue docs: `html .example { color: red; } hi ` With this, the example` class will only ever apply within this component. This is achieved by added a unique data attribute to all elements within the component, so the normal CSS cascade is still applied. External styles can still impact the design of this component, but its scoped styles cannot leak out to other components. Deep Styles This leads to an interesting problem. If our component's styles are scoped, what about children components? By default, they would not receive any styling from our scoped styles. However, Vue provides a way to do that. Let's look at an example below. `html Card Title Lorum ipsum dolor sit amet header :deep(.card-title) { font-weight: bold; } section { padding 2rem; } Title ` By using the :deep()` pseudo class, we are able to tell Vue that this particular class (`.card-title`) should not be scoped. Because the special ID is still applied to the root element (`header`), the style is still scoped, but it is available for any child component beneath it. Slotted Styles A problem I've run into in many situations is that I have a component being injected with slots, but I cannot control the styling of it like I want. Vue provides a solution for this as well with slotted styles. Let's review the above example, but this time we'll add a slotted style to our Title.vue component. `html Card Title Lorum ipsum dolor sit amet header :deep(.card-title) { font-weight: bold; } section { padding 2rem; } Title :slotted(h1) { font-size: 3rem; } ` Here, we added the :slotted` pseudo class, so that any slotted `h1` tags have the correct style applied to them. This may be a contrived example, but consider needing to have different header styles for each header tag (or equivalent CSS class). The Title.vue component can manage all of these styles, rather than relying on the consumer of these components to pass in the correct class or styling. Global Styles Of course, sometimes you need to apply styles globally, even within a scoped component. Vue provides us with two different ways to handle this: the :global` pseudo selector and multiple style blocks. `:global` Within a scoped style block, if you only need to provide one class as a global value, you can use the :global` pseudo selector to note that the style should not be scoped. From the Vue docs: `html :global(.red) { color: red; } ` Multiple style blocks There is also nothing stopping you from having multiple style blocks within your Vue component. Simply create another ` tag, and put your global styles in there. `html / global styles */ / local styles */ ` Style Modules If you're coming from React, you may be more familiar with CSS modules, where you import a CSS file and access its classes as a JavaScript object. The same can be done within Vue by using ` instead of ``. Here's an example from the Vue docs: `html This should be red .red { color: red; } ` This can be particularly nice to work with, so that you aren't passing strings around in your classes (which are prone to errors and typos). Vue also allows you to rename what the object is, so that you don't need to access them with $style` in your template if you don't want to. Dynamic CSS Values The latest feature in Vue is state-driven dynamic CSS values. There is a trend in modern CSS to use custom properties as a way to dynamically update the value of some CSS property. This can allow our CSS to be more flexible, and interact nicely with our other application code. Let's look at an example component that renders a progress bar: `html Progress {{ progress }}% import { watch } from 'vue' const props = defineProps({ progress: { type: Number, required: true } }) watch(props.progress, (value) => document .documentElement .style .setProperty('--complete-percentage', value + '%'), { immediate: true }) .progress-bar { background-color: #ccc; border-radius: 13px; padding: 3px; } .progress-bar > div { background-color: #000; width: var(--complete-percentage); height: 8px; border-radius: 10px; transition-property: width; transition-duration: 150ms; } ` This component takes in a number (progress`), then both displays that number and updates a CSS custom property with the value. As the progress changes, the CSS property is continually updated to stay in sync with the JavaScript value. In Vue 3.2, however, we are provided with a special CSS function that does this whole thing for us! Take a look at the updated code: `html Progress {{ progress }}% const props = defineProps({ progress: { type: Number, required: true } }) .progress-bar { background-color: #ccc; border-radius: 13px; padding: 3px; } .progress-bar > div { background-color: #000; width: v-bind(props.progress); height: 8px; border-radius: 10px; transition-property: width; transition-duration: 150ms; } ` By using v-bind(props.progress)`, we have elimited the need for our custom watcher, and it's clear that our CSS is being kept in sync with the value of `props.progress`. Under the hood, Vue is doing the same thing for us with a custom property, but it's so much nicer than having to write it ourselves. Conclusion CSS is a complicated language in practice, and mixing it with JavaScript makes things even more complex. Vue provides developers with the tools to handle CSS in a reliable and predictable way, which encourages building in a component-based architecture. Next time you're running into trouble with CSS in Vue, see if one of these techniques can be useful to you!...

Testing a Fastify app with the NodeJS test runner cover image

Testing a Fastify app with the NodeJS test runner

Introduction Node.js has shipped a built-in test runner for a couple of major versions. Since its release I haven’t heard much about it so I decided to try it out on a simple Fastify API server application that I was working on. It turns out, it’s pretty good! It’s also really nice to start testing a node application without dealing with the hassle of installing some additional dependencies and managing more configurations. Since it’s got my stamp of approval, why not write a post about it? In this post, we will hit the highlights of the testing API and write some basic but real-life tests for an API server. This server will be built with Fastify, a plugin-centric API framework. They have some good documentation on testing that should make this pretty easy. We’ll also add a SQL driver for the plugin we will test. Setup Let's set up our simple API server by creating a new project, adding our dependencies, and creating some files. Ensure you’re running node v20 or greater (Test runner is a stable API as of the 20 major releases) Overview `index.js` - node entry that initializes our Fastify app and listens for incoming http requests on port 3001 `app.js` - this file exports a function that creates and returns our Fastify application instance `sql-plugin.js` - a Fastify plugin that sets up and connects to a SQL driver and makes it available on our app instance Application Code A simple first test For our first test we will just test our servers index route. If you recall from the app.js` code above, our index route returns a 501 response for “not implemented”. In this test, we're using the createApp` function to create a new instance of our Fastify app, and then using the `inject` method from the Fastify API to make a request to the `/` route. We import our test utilities directly from the node. Notice we can pass async functions to our test to use async/await. Node’s assert API has been around for a long time, this is what we are using to make our test assertions. To run this test, we can use the following command: By default the Node.js test runner uses the TAP reporter. You can configure it using other reporters or even create your own custom reporters for it to use. Testing our SQL plugin Next, let's take a look at how to test our Fastify Postgres plugin. This one is a bit more involved and gives us an opportunity to use more of the test runner features. In this example, we are using a feature called Subtests. This simply means when nested tests inside of a top-level test. In our top-level test call, we get a test parameter t` that we call methods on in our nested test structure. In this example, we use `t.beforeEach` to create a new Fastify app instance for each test, and call the `test` method to register our nested tests. Along with `beforeEach` the other methods you might expect are also available: `afterEach`, `before`, `after`. Since we don’t want to connect to our Postgres database in our tests, we are using the available Mocking API to mock out the client. This was the API that I was most excited to see included in the Node Test Runner. After the basics, you almost always need to mock some functions, methods, or libraries in your tests. After trying this feature, it works easily and as expected, I was confident that I could get pretty far testing with the new Node.js core API’s. Since my plugin only uses the end method of the Postgres driver, it’s the only method I provide a mock function for. Our second test confirms that it gets called when our Fastify server is shutting down. Additional features A lot of other features that are common in other popular testing frameworks are also available. Test styles and methods Along with our basic test` based tests we used for our Fastify plugins - `test` also includes `skip`, `todo`, and `only` methods. They are for what you would expect based on the names, skipping or only running certain tests, and work-in-progress tests. If you prefer, you also have the option of using the describe` → `it` test syntax. They both come with the same methods as `test` and I think it really comes down to a matter of personal preference. Test coverage This might be the deal breaker for some since this feature is still experimental. As popular as test coverage reporting is, I expect this API to be finalized and become stable in an upcoming version. Since this isn’t something that’s being shipped for the end user though, I say go for it. What’s the worst that could happen really? Other CLI flags —watch` - —test-name-pattern` - TypeScript support You can use a loader like you would for a regular node application to execute TypeScript files. Some popular examples are tsx` and `ts-node`. In practice, I found that this currently doesn’t work well since the test runner only looks for JS file types. After digging in I found that they added support to locate your test files via a glob string but it won’t be available until the next major version release. Conclusion The built-in test runner is a lot more comprehensive than I expected it to be. I was able to easily write some real-world tests for my application. If you don’t mind some of the features like coverage reporting being experimental, you can get pretty far without installing any additional dependencies. The biggest deal breaker on many projects at this point, in my opinion, is the lack of straightforward TypeScript support. This is the test command that I ended up with in my application: I’ll be honest, I stole this from a GitHub issue thread and I don’t know exactly how it works (but it does). If TypeScript is a requirement, maybe stick with Jest or Vitest for now 🙂...