Search results for "Josh Justice":

Are you satisfied with your test suites? If you said no, you’re not alone—most developers aren’t. And testing in React Native is harder than on most platforms. How can you write JavaScript tests when the JS and native code are so intertwined? And what in the world are you supposed to do about that persistent act() warning? Faced with these challenges, some teams are never able to make any progress testing their React Native app, and others end up with tests that don’t seem to help and only take extra time to maintain.
But it doesn’t have to be this way. React Native Testing Library (RNTL) is a great library for component testing, and with the right mental model you can use it to implement tests that are low-cost and high-value. In this three-hour workshop you’ll learn the tools, techniques, and principles you need to implement tests that will help you ship your React Native app with confidence. You’ll walk away with a clear vision for the goal of your component tests and with techniques that will help you address any obstacle that gets in the way of that goal.you will know:- The different kinds React Native tests, and where component tests fit in- A mental model for thinking about the inputs and outputs of the components you test- Options for selecting text, image, and native code elements to verify and interact with them- The value of mocks and why they shouldn’t be avoided- The challenges with asynchrony in RNTL tests and how to handle them- Options for handling native functions and components in your JavaScript tests
Prerequisites:- Familiarity with building applications with React Native- Basic experience writing automated tests with Jest or another unit testing framework- You do not need any experience with React Native Testing Library- Machine setup: Node 16.x or 18.x, Yarn, be able to successfully create and run a new Expo app following the instructions on https://docs.expo.dev/get-started/create-a-new-app/

React Testing Library is a great framework for React component tests because there are a lot of questions it answers for you, so you don’t need to worry about those questions. But that doesn’t mean testing is easy. There are still a lot of questions you have to figure out for yourself: How many component tests should you write vs end-to-end tests or lower-level unit tests? How can you test a certain line of code that is tricky to test? And what in the world are you supposed to do about that persistent act() warning?
In this three-hour workshop we’ll introduce React Testing Library along with a mental model for how to think about designing your component tests. This mental model will help you see how to test each bit of logic, whether or not to mock dependencies, and will help improve the design of your components. You’ll walk away with the tools, techniques, and principles you need to implement low-cost, high-value component tests.
Prerequisites:- Familiarity with building applications with React- Basic experience writing automated tests with Jest or another unit testing framework- You do not need any experience with React Testing Library- Machine setup: Node LTS, Yarn

React Testing Library is a great framework for React component tests because there are a lot of questions it answers for you, so you don’t need to worry about those questions. But that doesn’t mean testing is easy. There are still a lot of questions you have to figure out for yourself: How many component tests should you write vs end-to-end tests or lower-level unit tests? How can you test a certain line of code that is tricky to test? And what in the world are you supposed to do about that persistent act() warning?
In this three-hour workshop we’ll introduce React Testing Library along with a mental model for how to think about designing your component tests. This mental model will help you see how to test each bit of logic, whether or not to mock dependencies, and will help improve the design of your components. You’ll walk away with the tools, techniques, and principles you need to implement low-cost, high-value component tests.
Table of contents- The different kinds of React application tests, and where component tests fit in- A mental model for thinking about the inputs and outputs of the components you test- Options for selecting DOM elements to verify and interact with them- The value of mocks and why they shouldn’t be avoided- The challenges with asynchrony in RTL tests and how to handle them
Prerequisites- Familiarity with building applications with React- Basic experience writing automated tests with Jest or another unit testing framework- You do not need any experience with React Testing Library- Machine setup: Node LTS, Yarn

TypeScript has a powerful type system with all sorts of fancy features for representing wild and wacky JavaScript states. But the syntax to do so isn't always straightforward, and the error messages aren't always precise in telling you what's wrong. Let's dive into how many of TypeScript's more powerful features really work, what kinds of real-world problems they solve, and how to wrestle the type system into submission so you can write truly excellent TypeScript code.

In this workshop you’ll learn why we created FlashList at Shopify and how you can use it in your code today. We will show you how to take a list that is not performant in FlatList and make it performant using FlashList with minimum effort. We will use tools like Flipper, our own benchmarking code, and teach you how the FlashList API can cover more complex use cases and still keep a top-notch performance.You will know:- Quick presentation about what FlashList, why we built, etc.- Migrating from FlatList to FlashList- Teaching how to write a performant list- Utilizing the tools provided by FlashList library (mainly the useBenchmark hook)- Using the Flipper plugins (flame graph, our lists profiler, UI & JS FPS profiler, etc.)- Optimizing performance of FlashList by using more advanced props like `getType`- 5-6 sample tasks where we’ll uncover and fix issues together- Q&A with Shopify team

We know that React is for the web and React Native is for Android and iOS. But have you heard of react-native-web—for writing an app for Android, iOS, and the web in one codebase? Just like React Native abstracts away the details of iOS and Android, React Native Web extracts away the details of the browser as well. This opens up the possibility of even more code sharing across platforms.
In this workshop you’ll walk through setting up the skeleton for a React Native Web app that works great and looks awesome. You can use the resulting codebase as a foundation to build whatever app you like on top of it, using the React paradigms and many JavaScript libraries you’re used to. You might be surprised how many types of app don’t really require a separate mobile and web codebase!
What's included1. Setting up drawer and stack navigators with React Navigation, including responsiveness2. Configuring React Navigation with URLs3. Setting up React Native Paper including styling the React Navigation drawer and headers4. Setting up a custom color theme that supports dark mode5. Configuring favicons/app icons and metadata6. What to do when you can’t or don’t want to provide the same functionality on web and mobile
Prerequisites- Familiarity with building applications with either React or React Native. You do not need to know both.- Machine setup: Node LTS, Yarn, be able to successfully create and run a new Expo app following the instructions on https://docs.expo.dev/get-started/create-a-new-app/