Learn Jest, Ruby and Scikit-learn

jest

Jest is a fast and safe testing framework with a focus on simplicity. 
This lesson will walk you through how to add jest to your application by running `yarn add --dev jest` followed by updating your `package.json` to be able to run your tests on the console by using the `yarn test` script.
This lesson covers how to create your first test by creating your first block that groups several related tests with `describe` and then adding your first test method using either the `it` or `test` keyword.

Add Jest to Your Application and Create Your First Test

The pluggable linting utility for JavaScript and JSX.

eslint

We can leverage GitHub Actions to automate the running of all of our accessibility auditing tools as part of a Continuous Integration (CI) workflow. 

Auditing tools will only catch a percentage of potential accessibility issues, it is no replacement for manual testing.  But being able to automate the auditing will add efficiencies to our testing and provide an early warning system that can be run much more frequently than it’s practical to perform manual testing.  Additionally, we can use our CI suite as a safety net to prevent code changes that break accessibility from being able to be merged.

## Resources
* https://app.egghead.io/lessons/react-set-up-eslint-to-audit-accessibility-issues-in-react
* https://docs.cypress.io/guides/continuous-integration/github-actions#Basic-Setup
* https://github.com/cypress-io/github-action

Automate Accessibility Audits with GitHub Actions

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

We can add accessibility testing to our `jest` unit tests with `jest-axe` which gives us:

* An easy way to automate accessibility auditing
* the flexibility to audit at any level of our code, as low as an element and as high as a component representing an entire page of our app
* A safety net for any accessibility regressions

Here we'll see how to use `jest-axe` with `react-testing-library` to render the components for `jest-axe` to audit for accessibility.

The React Testing Library is a very light-weight solution for testing React components. It provides light utility functions on top of react-dom and react-dom/test-utils, in a way that encourages better testing practices.

## Resources
* jest-axe: https://github.com/nickcolley/jest-axe
* react-testing-library: https://testing-library.com/docs/react-testing-library/intro/

Write Better Unit Tests with react-testing-library and jest-axe

We can add accessibility testing to our `jest` unit tests with `jest-axe` which gives us:

* An easy way to automate accessibility auditing.
* The flexibility to audit at any level of our code, as low as an element and as high as a component representing an entire page of our app.
* A safety net for any accessibility regressions.

Here we'll see how to use `jest-axe` with `enzyme` to render the components for `jest-axe` to audit for accessibility.

Enzyme is a JavaScript Testing utility for React that makes it easier to test your React Components' output. You can also manipulate, traverse, and in some ways simulate runtime given the output.

## Resources
* jest-axe: https://github.com/nickcolley/jest-axe
* enzyme: https://enzymejs.github.io/enzyme

Write Unit Tests for Accessibility Using jest-axe and enzyme

We can add accessibility testing to our `jest` unit tests with `jest-axe` which gives us:

* An easy way to automate accessibility auditing.
* The flexibility to audit at any level of our code, as low as an element and as high as a component representing an entire page of our app.
* A safety net for any accessibility regressions.

Here we'll see how to use `jest-axe` with `ReactDOM` to render components for `jest-axe` to audit for accessibility.

## Resources
* https://github.com/nickcolley/jest-axe

Render Components with ReactDOM to Write Tests with Jest and jest-axe

Best practices for building & testing redux applications have changed dramatically over time. This course aims to be a comprehensive yet understandable resource for those seeking to improve the testing of their redux applications.

This course is broken up into three parts.

The intro is look at how to add jest to an existing react redux application that was built on top of [vite](https://vitejs.dev/). We cover basic functionality like [watch mode](https://jestjs.io/docs/cli#--watch) and generating and using [code coverage](https://jestjs.io/docs/cli#--coverageboolean) to inform our testing strategy.

The first section covers the specifics of unit testing the redux code in our application. We'll go over how to test reducers, selectors and thunks. As part of this we'll touch on mocking APIs and using [Redux Mock Store](https://github.com/reduxjs/redux-mock-store) as well as running actions through our applications' actual reducers to broaden our test coverage.

Finally we'll look at how we can test our redux connected react components using the various utilities that come with the [React Testing Library](https://testing-library.com/docs/react-testing-library/intro/). We'll cover simulating various kinds of user input with the [user-event module](https://testing-library.com/docs/ecosystem-user-event), populating our redux store with test data, using [jest spy](https://jestjs.io/docs/jest-object#jestspyonobject-methodname), how to wait for asynchronous tasks to complete, and several approaches for finding & asserting that visual elements exist on the page.

This course is built on top of content that was created for the [Modern Redux with RTK and TypeScript](https://app.egghead.io/playlists/modern-redux-with-redux-toolkit-rtk-and-typescript-64f243c8) course and I highly recommend you start there if you haven't completed it already. 

I'm confident you will level up your redux testing abilities if  watch these lessons and practice coding each of them as you go.

Intro to Confidently Testing Redux Applications with Jest & TypeScript

Intermission Pep Talk - Testing Redux Applications

The [reselect module](https://github.com/reduxjs/reselect) popularized a pattern of memoized redux selectors. Now that pattern is baked into Redux Toolkit with its [createSelector](https://redux-toolkit.js.org/api/createSelector) method, which is used by the `getMemoizedNumItems` selector we're testing here.

Any selectors created with `createSelector` come with these two additional methods `recomputations()` and `resetRecomputations()`. These methods keep track of how many teams your data was recomputed and are essential for testing these selectors.

Some additional examples on testing memoized selectors can be found here:
https://github.com/reduxjs/reselect#q-how-do-i-test-a-selector



----

The createSelector method first takes any number of "input selectors" which gather data from your redux store and then for its final arguments takes an additional selector which has for its inputs the result of those input selectors.

The memoization is broken if either the initial state is unchanged OR if the any of the  results of the input selectors are unchanged. It uses `===` equality and not any sort of nested equality checking so `state` and `{ ...state }` would not be considered the same and always would recompute. On the flip side passing in `state` and then running `state.count++` would not trigger a recompute automatically, because the `state` object reference has not changed and `===` would pass. It definitely tripped me up a few times, so keep an eye out for issues with this.




Unit Testing a Memoized Redux Selector Built with Reselect/RTK

Redux is a predictable state container for JavaScript apps.
It helps you write applications that behave consistently, run in different environments (client, server, and native), and are easy to test.

redux

There are several ways to mock APIs for our tests.

Here we're using [jest.mock](https://jestjs.io/docs/es6-class-mocks#calling-jestmock-with-the-module-factory-parameter) with the module factory parameter to a new mocked module to replace our original. This helps us avoid problems like servers taking a long time and node.js not having fetch built-in.

When using mocks this way it's important to note that this mocked module is only going to show up for the tests executed in this file. Other test suites will continue to receive the original implementation of app/api. 

Other approaches to mock APIs include mocking out `window.fetch` or using [Mock Service Worker](https://mswjs.io/docs/getting-started/integrate/node) to provide a more robust API implementation. However, the approach we took here makes sense for our use case. We have a simple API surface, it lives in a single file, we never call `fetch` directly and we don't need a lot of bells and whistles (like responding to different routes or query parameters). So for that reason this approach and the [spyOn](https://jestjs.io/docs/jest-object#jestspyonobject-methodname) approach used in some of the later lessons actually works really well.

If you're using [Apollo](https://www.apollographql.com/) or [ReactQuery](https://react-query.tanstack.com/) or [SWR](https://swr.vercel.app/) to handle your data, then you almost certainly should use [Mock Service Worker](https://mswjs.io/docs/getting-started/integrate/node) instead of the jest.mock approach.

Mocking out our API Helper with jest.mock

Code coverage is an important part of any test setup. One of the jest framework's innovations is built-in test coverage support. In this lesson I demonstrate using the [collectCoverageFrom](https://jestjs.io/docs/configuration#collectcoveragefrom-array) configuration option to improve jest's coverage support for TypeScript files and then demonstrate using `npx jest --coverage` to run code coverage as well as `npm test -- --coverage`, which does the same thing.

At the end I briefly mention the [collectCoverage](https://jestjs.io/docs/configuration#collectcoverage-boolean) flag which seems like you'd want to always just have on, but in practice is annoying. That's because coverage takes several extra to process and I rarely need my code coverage run, so it just makes the testing feedback loop a lot slower. For a build-only config it might make sense to leave on.

----

There's a [pretty good question on stackoverflow](https://stackoverflow.com/questions/43046885/what-does-do-when-running-an-npm-command) that covers using `--` with `npm test` that you might want to check out.

Here's an explanation of [how npx differs from npm](https://medium.com/@maybekatz/introducing-npx-an-npm-package-runner-55f7d4bd282b).


Configuring Code Coverage for TypeScript Files in Jest

Jest has a [watch mode](https://jestjs.io/docs/cli) that can really speed up test development. It will automatically run your tests as you save your test files. And it has a built-in pattern option to allow you to only focus on tests for a particular file. This approach works well in combination with [test.todo](https://jestjs.io/blog/2019/01/25/jest-24-refreshing-polished-typescript-friendly#testtodo) where you can stub out a number of tests and then code on them until they all pass.

Most of what is being done in these tests we've already seen before and it's important to note that I'm doing only the most basic of testing here. For each of these actions it wouldn't be uncommon in production to have 3-6 tests instead of just one.

It's important to note that `it` and `test` are aliases of one another so `it.todo` and `test.todo` both work seamlessly and are just a matter of preference. *Usually* when I'm doing unit testing I'll stick with `describe` and `it`, which commonly go together and I use `test` without `describe` when I'm testing react components with [React Testing Library](https://testing-library.com/docs/react-testing-library/intro).

Using Jest in Watch Mode with test.todo to Test a Redux Reducer

The app is built on top of [vite](https://vitejs.dev/) instead of the more popular [create react app](https://reactjs.org/docs/create-a-new-react-app.html). The benefit of vite is that it installs and builds extremely quickly. One of the downsides of vite is that it doesn't come with any out-of-the-box testing support. It also has its own [esbuild-based compiler](https://vitejs.dev/guide/features.html#typescript), which is not currently compatible with jest, so we have to configure JSX & TypeScript support for jest even though `vite` handles that already for our app.

This lesson requires installing a handful of modules:
```
npm install -D jest
npm install -D @testing-library/react @testing-library/jest-dom @testing-library/user-event
npm install -D @babel/preset-react @babel/preset-typescript @babel/preset-env
npm install -D identity-obj-proxy
```

Each of them serves an important purpose:

- [jest](https://jestjs.io/) _runs our tests_
- [@testing-library/react](https://testing-library.com/docs/react-testing-library/intro) adds the ability to render react components inside of our test environment
- [@testing-library/jest-dom](https://github.com/testing-library/jest-dom) _allows us to assert that components are in the DOM and contains certain text and classes_
- [@testing-library/user-event](https://testing-library.com/docs/ecosystem-user-event) _allows us to interact with rendered components programmatically_
- [@babel/preset-react](https://babeljs.io/docs/en/babel-preset-react), [@babel/preset-typescript](https://babeljs.io/docs/en/babel-preset-typescript), and [@babel/preset-env](https://babeljs.io/docs/en/babel-preset-env) allow us to use ES6 Modules, JSX, and TypeScript in our tests
- [identity-obj-proxy](https://github.com/keyz/identity-obj-proxy#identity-obj-proxy---) is helpful when rendering CSS modules so that we can see the original class names instead of obfuscated ones

We also have to add numerous config files such as `babel.config.js` and `jest-setup.ts` which are required to enable all of this functionality.

We put our `jest` config in our `package.json` file which works well, but you can also put it in a file named `jest.config.ts` or `jest.config.js`. See the [Jest Configuration Documentation](https://jestjs.io/docs/configuration) for more details about configuring jest.



Adding Jest with TypeScript Support to a Vite Application

In this lesson we go after the elusive goal of 100% test coverage by testing a few additional cases: error responses, empty error messages and the pending state that should exist between checkout being clicked and the API returning data.

The first two require special handling in our mock API:

```typescript
if (items.evilItem > 0) throw new Error();
if (items.badItem > 0) return { success: false };
```

In some ways these are arbitrary examples that may not exist in your other applications, but I wanted to demonstrate the fact that there are a lot of different ways an API might decide to communicate errors.

In general with AJAX calls a non-200 status response often gets thrown as an error and treated as an error case, but some APIs (such as graphql) include errors as part of a normal `200` response and need special handling. These lessons are meant to demonstrate what that might look like in your mocks.

Now it's useful to reiterate here that our simple API interface makes writing these mocks very easy, but in many cases something like [Mock Service Worker](https://mswjs.io/docs/getting-started/integrate/node) is a more appropriate way to mock out an API.

For our "pending" test, it's interesting what we lose when we stop focusing on actions fired (like in our previous 2 lessons) and instead focus purely on the resulting state. It makes looking at the intermediary state a bit more difficult. Here we work around that by calling `store.dispatch(thunk)` and saving the results of that to an `action` variable, which we `await` after doing an initial assertion. That `await` triggers our mock API to respond, so we can use the space between `dispatch` and `await` to peak into the pending state.

Additional Redux Thunk Unit Tests for Increased Code Coverage

In a lot of ways plain selectors like we're testing here are extremely simple to reason about. The only thing that's a little tricky is even though they're often written side-by-side with a reducer, they accept the `RootState` instead of the reducer state. When writing these tests with TypeScript you often find yourself using `as` to cast partial state into full `RootState` type.

Here we're doubly nesting our `describe` blocks and it works great and makes our test output nicely formatted.

Unit Testing a Basic Redux Selector

For this lesson we focus on running our thunks through our app's reducer methods to test both the thunks and the reducers in a single test. Testing our thunks this way gives us more confidence they are working exactly as we expect and its less code for us to write. The main challenge we face in using our redux store this way is that we need to preload it with state.

To make that simpler we create two helper utilities: `getStoreWithState()` and `getStateWithItems()`. We're going to continue to use these utilities throughout our lessons. 

You'll notice I keep referring to the generated store as our "real redux store", even though we aren't relying on the `store` variable but generating a new store with the same reducers. What I really mean here is that our store has the same middleware and reducers as our app's store. Generating a new store for each test is important so that they can have their own state that don't conflict with other tests.

**Note**: It's also possible to generate the app's `store` variable with `getStoreWithState()`, but it makes the TypeScript syntax more complex and it seemed like it wouldn't add a lot of value.

Unit Testing Redux Thunks and Associated Reducer Methods using Your App's Redux Store

[Redux Mock Store](https://github.com/reduxjs/redux-mock-store) is a library that provides two important capabilities. 1. It makes it easy to pre-load state. 2. It keeps track of which actions were fired. We take advantage of both here for testing our thunk, in what amounts to just a slightly cleaner approach than using `jest.fn()` as we did in our previous lesson.

[Redux Mock Store](https://github.com/reduxjs/redux-mock-store) is more commonly used as a way to test redux-connected components, but also works anytime we need an easy way to confirm that certain actions are fired into our redux store.


While it does make it easy to populate a redux store and inspect which actions were fired, redux mock store doesn't have any reducers, so you can't use it in tests where you want your components to update in response to any actions. It's strictly a read-only store. Another challenge of using redux mock store is that it needs to be configured separately from your primary redux store. There may be cases where you'll have a middleware on your production redux store, but forget to add it to your mock store, leading to tests that don't match the behavior of your application. For these reasons I think it's generally better run both unit and integration tests against a store with your actual reducers hooked up when at all possible.

Unit Testing Redux Thunks using Redux Mock Store

The [reselect module](https://github.com/reduxjs/reselect) popularized a pattern of memoized redux selectors. Now that pattern is baked into Redux Toolkit with its [createSelector](https://redux-toolkit.js.org/api/createSelector) method, which is used by the `getTotalPrice` selector we're testing here.

Any selectors created with `createSelector` come with these two additional methods `recomputations()` and `resetRecomputations()`. These methods keep track of how many times your selector was recomputed and are essential for testing.

The createSelector method first takes any number of "input selectors" which gather data from your redux store and then for its final arguments takes an additional selector which has for its inputs the result of those input selectors.

A cached response will be used, if one exists, when either the root state passed in to the selector is unchanged or if any of the results of the input selectors remain unchanged between calls. It uses `===` equality and not any sort of nested equality checking so `state` and `{ ...state }` would not be considered the same and would always recompute. On the flip side passing in `state` and then running `state.count++` would not trigger a recompute automatically, because the `state` object reference has not changed and `===` would remain true. Writing tests for my memoized selectors definitely helped me better understand this behavior.

Some additional examples on testing memoized selectors can be found here:
https://github.com/reduxjs/reselect#q-how-do-i-test-a-selector




Unit Testing a Memoized Selector that Derives Data from Multiple Reducers

How to properly test thunks seems to be the source of a lot of confusion. Usually an API needs to be mocked and then there are numerous ways to actually run the tests. This lesson showcases the most basic approach which relies on [jest mock functions](https://jestjs.io/docs/mock-functions) and avoids hitting a redux store or reducer. 

For this lesson we're testing a thunk created using Redux Toolkit's [createAsyncThunk](https://redux-toolkit.js.org/api/createAsyncThunk) method. The test should continue work completely untouched even if we build the thunk by hand.

The [mock property](https://jestjs.io/docs/mock-functions#mock-property) of the `jest.fn()` we create here for our mock dispatch ends up doing most of the work. The nested array inside of the `calls` property measuring first "times called" and then "arguments passed" is a little bit confusing, but extremely powerful!

My least favorite part of this was needing to pass the third `extra` argument to our thunk to satisfy TypeScript. The other frustrating part was having to build a complete `RootState` object to pass into our `getState` method. We'll solve that in a later lesson by creating a `getStateWithItems` helper.

Unit Testing Redux Thunks with a Mock Dispatch Function

JavaScript® (often shortened to JS) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages, but used in many non-browser environments as well such as node.js or Apache CouchDB. It is a prototype-based, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.

javascript

One of the strengths of [Nx](https://nx.dev) is that it provides you easy access to some of the best tooling available. As such, whenever you generate a new app or lib inside an Nx workspace, it automatically preconfigures Jest for you and even sets up some pre-generated tests.

Run Jest tests for a React app with Nx

Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Controller (MVC) pattern.

rails

If you make a mistake when naming your database column, and have data that you want to keep unchanged. You can use the change method with the rename_column definition in your migrations files to update a single column name in your database.

Rename A Database Column with Ruby on Rails Active Record Migrations

If you're not careful you can write a test that's worse than having not tests at all. In this lesson we'll learn why that is and how you can avoid it by making sure your test can fail.

This is based on my blog post: [Make Your Test Fail](https://kentcdodds.com/blog/make-your-test-fail)

Make Your Test Fail

When we import assets in React components outside of the `public` folder that Nitro reads for assets by default when running the development server we need to tell Nitro how to find them with the `devProxy` configuration option.

```typescript
export default defineNitroConfig({
  renderer: './renderer.ts',
  devProxy: {
    '/app/assets': 'http://localhost:5173/app/assets'
  }
})
```

This is ultimately inadequate in scenarios where you want to import assets arbitrarily and have them "just work" but works in a pinch.



Use devProxy in Nitro Config to Serve Static Imported Assets in Dev Mode via Vite

Learn how to use devProxy in Nitro Config with Vite to serve static assets in React components in dev mode.

Start with a basic Vite React TypeScript app and enhance it for production use by integrating Nitro as the server. 

This requires a custom Vite plugin for nitro as well as a custom renderer and manually creating Nitro config.

The other way to approach this would be to add Vite to a Nitro app instead. Same basic result.

The [Nitro config reference](https://nitro.unjs.io/config) is a great read of you'd like to explore more options.


Configure a Vite React TypeScript Application on a Basic Nitro Server

Configure a Vite React TypeScript app by integrating Nitro for production, using custom plugins, renderers, and configs.

Quick Get Started style introduction to Vite using `pnpm create vite` with the React TypeScript template.

See [more in the official docs](https://vite.dev/guide/).

Create a Vite App with the React TypeScript Preset

Quick guide to start a Vite app using React TypeScript template with pnpm.

Over the years, your application have grown huge. Sometimes, really HUGE.

Many developers have contributed to the codebase. One day they pushed one coding style, a different one another day. Sometimes even different patterns and solutions for similar problems.

You want to keep your codebase consistent. In the Angular ecosystem, there were well established patterns for doing things the right way ™️. But the old solutions are being challenged by signal-based approach.

Eventually, you ask yourself the key question: **Should you integrate with the NEW solutions or stick to the battle-tested ones, but already considered LEGACY**?

That's a very good question indeed. Don't rush with architectural decisions 🤓.

## 👉 First, think of what problems you want to solve by introducing the change.

Do you have 1k LoC Angular components? Maybe even 2k? Do you and your team enjoy working with these? 😏

Where does the **domain logic and state management code** belong to - do you have a clear guidance on which code should be put where? Have you spot that different devs implement similar features in totally different ways?

Do you keep on asking the same questions over and over again: **whether this certain piece of code** should be **imperative** (plain old object properties and variables) or **reactive** (streams)? It'd be nice to keep all thinga reactive, but more often than not, it introduces complexity.

## 👉 Second, think of long-term consequences.

You are going to have more than one way to **manage the state**. But is that really an issue? If your codebase is modular, separate modules should not depend on each other in any way. Inner abstractions of one should be invisible to the other, etc.

You are going to introduce a **new tool**. On one hand, you need to learn it, and so does your team. But on the other hand, it's a breathe of fresh air. And it's useful to question the way you've been doing things so far. Maybe there's a more effective way?

You are going to embrace signal-based APIs. And that means taking taking advantage of Zoneless Angular. This means using all modern Angular APIs. And you know that signals are the future. Why would you want to stick to the **less performant, less type-safe, less flexible and, objectively, less effective solutions**?

## 👉 Finally, plan your INCREMENTAL integration.

INCREMENTAL is the absolute keyword here. You don't want to tell your PM you need to stop delivering features because of a refactor.

Actually, there's no need for a "refactor". Just pick the first new feature to be implemented. Or pick the one that needs to be extended.

NGRX Signal Store allows you to create both very simple & small stores, as well as bigger ones. **Composition** is the key here.

**Start simple**.

Create a `withState` section with the signals that hold the state. That's already reactive. And relatively simple.

```ts
const initialState: CartState = {
  items: ...,
  rebate: ...,
}

export const CartStore = signalStore(
  withState(initialState)
);
```

Create a `withMethods` section to provide ways to change the state:

```ts
export const CartStore = signalStore(
  ...
  withMethods((store) => ({
    addItem(item: ShoppingItem): void {
      patchState(store, (state) => ({ items: [ ...state.items, item ] }));
    },
    ...
);
```

Create a `withComputed` section to provide all derived computations:

```ts
export const CartStore = signalStore(
  ...
  withComputed(({ items }) => ({
    totalPrice: computed(() => items().reduce(...))
    ...
);
```

**Start simple**.

Now you can (literally) **`inject` this code into your existing solution**. All you need is to inject your brand new NGRX Signal Store implementation into a component, or a service:

```ts
@Injectable()
class ExistingBigService {
  cartStore = inject(CartStore)
  //...  
}
```

and that's it! What's beatiful is that NGRX Signal Store should remain an implementation details (of a component, service, etc). It **shouldn't leak outside to the entire application unintentionally**. Small NGRX Signal Stores help us to **keep logic more modular**.

Don't hesitate - give NGRX Signal Store a try! Start with the [_**Scalable Signals Angular Architecture with NGRX Signal Store**_](https://egghead.io/courses/scalable-signals-angular-architecture-with-ngrx-signal-store-a33abd39) course now!

Integrating NGRX Signal Store with an existing Angular application


Integrate NGRX Signal Store into your Angular app incrementally for modular, reactive state management. Improve consistency and performance with modern APIs.

In React 19, managing script tags efficiently within components can lead to performance enhancements and simpler code structures.

Originally, using script tags directly in a React component involved complex setups, like using `useEffect` to dynamically add JavaScript code. For instance, a component might dynamically inject script tags to load external widgets. This approach, while functional, resulted in multiple script tags and duplicate iframe elements. This duplication not only cluttered the output but also negatively impacted performance by loading scripts multiple times.

The workaround for this would be to manually hoist any common scripts and maybe load them when they weren't needed by any components.

With React 19 we now have a more effective method. This involves directly placing the script tag within the React component's return statement. This approach ensures that React handles the script loading, avoiding the duplication of script tags.

By implementing the script tags this way, the loading initiator becomes React DOM, which efficiently manages script loading and deduplication. This setup prevents multiple requests for the same script when the component is rendered multiple times, enhancing the overall application performance.

Furthermore, directly embedding the script tag simplifies the code, making the component cleaner and more maintainable.

Efficiently Render Script Tags in React 19 Components

Learn how to efficiently render script tags in React 19 components to improve performance by avoiding duplicate script loads and simplifying your code.

Let's learn how to dynamically manage title tags in React 19 applications. Rendering `<title>` dynamically is simple enough, however, a challenge arises when multiple title tags are present in the document, which can lead to issues with screen readers and search engine optimization (SEO). The solution presented involves ensuring that only one title tag is rendered at a time by using conditional rendering.

Also we need to make sure to have a single string within the title tag using a template literal, ensuring our HTML remains valid and optimized.


Deduplicate Title tags with React 19

Learn to manage multiple title tags in React 19 dynamically. Ensure accessibility and SEO by preventing duplicate title tags with clear examples.

In React 19, we can easily add a title tag like "Starship Deets" which then appears in the head section of the HTML even when we render it inside our components. This method also applies to meta tags such as character set and viewport settings, which are also lifted to the head section automatically.

This is an awesome feature because it maintains the same composition style we are familiar with in React components. It simplifies the handling of HTML head elements without needing extra setups like `useEffect` for accessing the head section. Even in situations where our components are rendering within a body element, like within a div, we can manage our head content directly within our components. React takes care of hoisting these elements where they need to go.


Hoist Title and Meta tags in React 19

Hoisting title and meta tags directly in React 19 components allows for simpler composition, similar to other React elements. Manage meta and title tags.

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Dax Raad, known for his strong opinions on Twitter, sat down for a chat about web dev, career moves, and building cool stuff. He's not afraid to throw some heat at popular tools like [Next.js](https://nextjs.org/), though he still helps people use it. Dax is particularly excited about local-first development, which he thinks isn't getting enough attention. He argues that sometimes the best web dev move is to step away from web dev entirely and explore other areas of programming.

When it comes to career growth, Dax encourages developers to think beyond the "web dev" label and see themselves as programmers capable of tackling any challenge. He advocates for trying out weird stuff and learning unusual languages, as these experiences can lead to unexpected opportunities. Taking smart risks in your career can open doors to awesome possibilities.

In the business world, Dax is a fan of making "asymmetric bets" - moves with low downside but huge potential upside. He applies this philosophy to his work on [SST](https://sst.dev/), reasoning that even if it fails, he'll walk away with valuable experience. He also emphasizes the importance of resisting quick payouts in favor of potentially bigger wins down the road.

Looking to the future of tech, Dax is betting on local-first development. He sees potential in getting in early on emerging technologies like [Solid.js](https://www.solidjs.com/). Building in public and making connections in new tech communities can pay off in unexpected ways.

Dax also challenges the notion of constant hyper-productivity in tech. He suggests balancing focused work with time for exploration and learning. Sometimes, he points out, what seems like a "dumb" choice (like learning a niche language) can turn out to be a smart career move in the long run.

## Good Stuff Mentioned

- [Next.js](https://nextjs.org/)
- [Vercel](https://vercel.com/)
- [SST](https://sst.dev/)
- [Elixir](https://elixir-lang.org/)
- [Solid.js](https://www.solidjs.com/)
- [RepliCache](https://replicache.dev/)
- [Linear](https://linear.app/)
- [Remix](https://remix.run/)
- [Shopify](https://www.shopify.com/)
- [React](https://react.dev/)

Developer Career Growth and Asymmetric Bets with Dax Raad

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Dev and Joel discuss React Miami conference, praising its fun atmosphere and location. They chat about React Server Components, with Dev sharing his experience building a mini framework. They talk about Vinxi, Nitro, and the unjs ecosystem as tools for creating custom frameworks. The conversation touches on Vue's popularity outside web dev circles and non-web dev conferences. They discuss the benefits of TypeScript and strongly-typed APIs. Dev mentions his upcoming talk on durable objects at [a conference in Dallas](https://x.com/DThompsonDev/status/1829674506237194456). They end by discussing WebSockets, PartyKit, and platform-specific frameworks.

## What's Good?

- [React Miami Conference](https://www.reactmiami.com/) 
- [Brenley Dueck's blog post on Simple RSC with Vinxi:](https://www.brenelz.com/posts/simple-rsc-with-vinxi/)
- [Vinxi](https://github.com/nksaraf/vinxi)
- [Nitro](https://nitro.unjs.io/guide/configuration)
- [unjs ecosystem](https://unjs.io/)
- [Solid Start](https://start.solidjs.com/)
- [TanStack Router](https://tanstack.com/router/latest) 
- [PartyKit](https://github.com/partykit/partykit) 
- [Durable Objects (Cloudflare)](https://developers.cloudflare.com/durable-objects/)
- [Flightcontrol](https://www.flightcontrol.dev/) 
- [SST](https://sst.dev/)
- [OpenNext](https://open-next.js.org/)

Nitro, Vinxi, and RSCs - What's Good with Dev Agrawal

**Note:** This course is being actively developed and more lessons will be added in the future.

Cursor is an AI-enhnaced code editor that allows you to call upon the robots to refactor or stub out functions for you with natural language. 

In this course, John will show you workflows that will save you time and effort by utilizing the features such as its mult-line editing and context.

In particular, by giving Cursor's AI the proper context, whether that's lines of code or multiple files, you'll get better output when trying to extend or refactor logic that's present.


Bite-size video tutorials for badass web developers.

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