Learn Eslint, Puppeteer and Turborepo

Turborepo is a fast build system for JavaScript and TypeScript.

turborepo

Turborepo is a task runner that helps speed up and manage your Monorepos. It's not a dependency management tool. It knows nothing about your dependencies. 

It speeds up Monorepos by using local and remote caching as well as incremental builds. It helps to manage your repo with very handy and easy-to-use scripts. 

Here is the [npm-workspaces repo](https://github.com/alejandronanez/npm-workspaces)

So let's hop in and learn about Turborepo!

Note: This course is a continuation of the course [Introduction to Monorepos with NPM Workspaces](https://egghead.io/courses/introduction-to-monorepos-with-npm-workspaces-c03f500b) where we initially build out the Monorepo that is used in this course. It is highly suggested to watch that course first before jumping into this one. 

What is Turborepo?

At the root of our project, we'll run `npm install turbo --save-dev` to install Turborepo.

We'll also look at how to configure Turborepo in the `turbo.json` file. We'll look into the [$schema](https://turborepo.org/schema.json) and how it affects our configuration. 

Install Turborepo in an Existing Monorepo

With our npm scripts, if utils can't build, then the dashboard and blog can't build or run their tests. Turborepo Pipelines changes that. Using the pipeline, we can set up caching, what our scripts depend on, and where we want our logs to be output. 

Also since we now have Turborepo installed and configured our pipelines, we can remove concurrently from our scripts and dependencies. 

Migrate NPM Scripts to Turborepo Pipelines

We are going to be going through Turborepo speeds up your builds and testing with caching. When a command is first run in Turborepo, it gets cached. This way if something has changed in one of your repos in your Monorepo, it will detect that change. For the repos that haven't changed, it will pull their info from the cache inside of `node_modules` instead of fully re-running that command. For the repo that has changed, it will run that command solely on that repo. 

Understand Turborepo Local Cache

It's fairly straight forward to create repo specific pipelines with Turborepo. The script goes like this: `{monorepo-name}/{repository}#{script-name}`. For example, if we wanted to run the typecheck command in just the dashboard repo, it would look like this: `@monorepo/dashboard#typecheck`. Lastly, we will make sure that it `dependsOn` the `utils#typecheck` pipeline. 

Create Repository Specific Turborepo Pipelines

A dependency graph is exactly what it sounds like! A visual graph created by Turborepo to show you your dependencies and what dependencies the projects rely on. For our Monorepo, we'll run `npx turbo run build --graph` in the root of our project and that will build the dependency graph for all of our projects.

We can also do one with a graphic but that requires the [Graphviz](https://graphviz.org/download/) library. We can edit our command to have some arguments: `npx turbo run build --graph=graph.pdf` and it will create a graphic in a .pdf file. 

Generate a Dependency Graph for Monorepos Using Turborepo

You can set up all of your specific pipelines in the turbo.json file, or you can filter through your pipelines in the terminal. If we wanted to run the `typecheck` command in just the `utils` package, our command would look like this: `npx turbo run typecheck --filter=@monorepo/utils`. You can remove `@monorepo` as long as the `utils` package is unique. 

Turborepo also gives you the option to filter your commands based on what files have changed on your branch using `--filter="[HEAD^1]". 

Now that we know a bit more about Turborepo, we can edit all of the scripts that we build in the previous course to use `turbo` instead of `npm`. 

Filter Pipeline Tasks Using Turborepo

By default, Turborepo will stop its execution if it runs into an error. We may not want that if we want Turborepo to continue in the projects that don't have an error. We can do this by adding the `--continue` flag to the end of our command. 

Prevent Turborepo Exiting Early on Failing Tasks

Another really good tool that Turborepo offers is the `--dry` flag. The `dry` flag will display details about the affected workspaces and tasks that would be run. It will help you to know what Turborepo is doing under the hood. 

Preview Turborepo Tasks at the Pipeline Level

The logs produced by Turborepo can get really really long. Turborepo give us a flag, `--output-logs` and if we add on the argument `new-only`, it shortens the logs to just the new information for the repositories that have changed. 

Shorten Turborepo Logs using --output-logs

Remote caching is key when coworking on a project. Using Turborepo, you can upload your cache to the cloud and use it everywhere else. For example, if your coworker switches to your branch and runs the build, they can have your most recent cache saving them time. 

We will start off by logging into Vercel and Turborepo then linking our Turborepo account to our Vercel account. Once that is done, we run `npx turbo link` to connect to our remote cache. Then in our Vercel dashboard, we will need to do some configuring to finish it up. 

Enable Remote Caching in Vercel

Now that we have Turborepo installed, configured, and we have some knowledge about it, let's deploy our two client-side applications, dashboard and blog, to Vercel. We'll link our Github to Vercel and point it towards our Monorepo. We'll then run through all of the configurations and commands needed to get our apps deployed. 

Deploy the Client-Side Apps in a Turborepo Monorepo to Vercel

Github Actions helps to automate the building, testing, and deploying of your applications. We'll configure our actions in the `ci.yml` file in a new directory called `.github/workflows`. When that file is configured, we can update our scripts in our package.json to run off of those. We will also need to make/set up our `TURBO_TOKEN` and our `TURBO_TEAM` which we will create on Vercel and Github. 

Enable Github Actions with Turbporepo Remote Caching

Now you might have a project that currently isn't in your Monorepo that you want to add to it. We can copy that project over into our `apps` folder and then update the `package.json` to update the name to make it consistent across our apps. We'll update the dev port to make sure it's not going to run on the same port as one of our other applications. Lastly, we'll update the build pipeline to include our new application. 

Migrate a VueJS Application to an Existing Turborepo Monorepo

The pluggable linting utility for JavaScript and JSX.

eslint

One of the other tools I use is Emmet. It's used for writing HTML much more quickly by using shorthand. It can also be used for JSX. VSCode also supports ESLint which we will use and configure in our VSCode `settings.json`. I will also set up Prettier as my default formatter for TypeScript and TypeScript React files. 

Configure Emmet, ESlint, and Prettier Extensions

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

Nx already comes with a default TypeScript setup. Although you can opt-out of that and generate plain JS based components, especially in a large setup TypeScript can be beneficial in uncovering potential issues early. To add an extra level, Nx also comes with preconfigured eslint for all the apps and libraries. In this lesson we're going to explore the lint setup and how it can be used.

Linting a React app with Nx

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

In this lesson you will learn how to use the eslint yeoman generator to scaffold a new plugin to provide custom rules for your project. 
You will also be able to check the basic skeleton for an eslint ruleand a working example rule to apply a naming convention for async functions.

Scaffold an eslint Plugin with Yeoman

OpenGraph images are the images you see when you paste a link into a social platform and it "unfurls" into an image, title, and description. This happens on Twitter, Discord, Slack, and many other platforms. This collection goes over everything from designing OpenGraph images in Figma, to implementing them in CodeSandbox, to returning headless browser screenshots from Netlify Functions, and finally using Cloudinary as a write-through cache. 

You will come away from this collection with the ability to ship an API that you can use on any of your sites, and also on-demand, that can generate images for not only OpenGraph unfurls, but also for Instagram, GitHub, and more. Using headless browsers with playwright to generate our images means we get full access to all the responsive power of CSS and all the logical power of JS to handle layout, importing assets like pngs, choosing different fonts, and more.

The image below is generated via the project you'll build and deploy in this course

![An example opengraph image](https://relaxed-payne-d1bfbe.netlify.com/opengraph?title=Building%20an%20OpenGraph%20image%20generation%20API%20with%20Cloudinary%20Netlify%20Functions%20and%20React&tags=figma,netlify%20functions,playwright&author=chrisbiscardi)

Building an OpenGraph image generation API with Cloudinary, Netlify Functions, and React

Puppeteer is a Node library which provides a high-level API to control headless Chrome or Chromium over the DevTools Protocol. It can also be configured to use full (non-headless) Chrome or Chromium.

puppeteer

When taking screenshots, it's important that the browser is big enough to show all of the content in the DOM that we want to screenshot. We can do this by setting the viewport.

Setting the viewport on a Playwright headless browser

We have a number of options to use when testing for accessibility issues concerning alternative text for images.  The react-axe library and axe browser extension will both report when an image is missing alternative text.  The tota11y browser extension will annotate any images that are missing alternative text.  Running eslint with the eslint-plugin-jsx-a11y plugin installed will report on any `<img>` elements missing an `alt` attribute.  Finally, we can use a screen reader to actually hear what is read when an image has focus.

Test for Image Alternative Text Accessibility Issues

Creating powerful and context-aware tools for Cursor IDE becomes straightforward when leveraging information directly from your current project. In this lesson, you'll learn how to build a custom MCP (model context protocol) tool that intelligently requests essential details—such as the current project path and conversation summaries—from your Cursor project.

Workflow demonstrated in this lesson:

- Define MCP tool parameters to request specific project details.
- Pass project path and conversation summaries into your MCP tool.
- Automatically write or update files within your current project using these parameters.

Key benefits:

- Automate tasks with precision based on your active project's context.
- Simplify interactions by creating AI-driven CLI commands tailored to your needs.
- Open endless possibilities for integrating external APIs and advanced automation.

Through this practical demonstration, you'll gain a versatile technique for enhancing your development workflow in Cursor IDE.

[https://github.com/johnlindquist/mcp-cursor-tool-starter](https://github.com/johnlindquist/mcp-cursor-tool-starter)

John Lindquist

Build MCP Tools Using Project Context for Custom Cursor IDE Automation

Setting up custom MCP (Machine Command Protocol) servers in Cursor can involve tedious steps, such as configuring node paths or referencing additional commands. This lesson shows how to streamline this process by bundling your MCP server directly into a standalone executable.

Workflow demonstrated in this lesson:

- Use a simple MCP server project starter.
- Run a single bundling command to create an executable.
- Right-click the generated executable, copy its full path, and add that directly to your Cursor settings.

Key benefits:

- Eliminates the need for complex node path configurations.
- Simplifies the setup and integration of custom MCP servers into Cursor.
- Makes the server executable instantly accessible within your Cursor environment.

By following this streamlined approach, you can quickly and easily integrate custom MCP servers into Cursor, making your development workflow cleaner and more efficient.

[https://github.com/johnlindquist/mcp-cursor-tool-starter]()

Easy MCP Server Setup in Cursor IDE with Bundled Executables

TanStack Router is the foundation for TanStack Start, which is gaining significant attention due to its innovative approach to application development.

This course focuses on getting effective TanStack Router, a modern and scalable routing solution for React applications. You will learn how to:
- set up and scaffold new applications,
- use file-based routing
- create nested routes
- manage dynamic route parameters and more.

The course covers advanced features like route loaders, caching strategies, and lifecycle hooks, which are crucial for enhancing application performance and user experience.

By understanding TanStack Router, you can build more efficient, type-safe, and maintainable applications, leveraging its integration with data fetching libraries like TanStack Query.

This knowledge is essential for developers looking to improve their routing skills and stay ahead in the field.

Tomasz Ducin

Up and Running with Tanstack Router and React

Learn TanStack Router for React: set up apps, use file-based routing, manage routes, and boost app performance.


In this lesson, we explore how TanStack Router integrates with the [native browser history API](https://developer.mozilla.org/en-US/docs/Web/API/History) to manage navigation.

As we navigate through different routes, the URL changes are stored in the browser's history, allowing users to use the forward and backward buttons to traverse their navigation history.

This functionality also **enables permalinks**, meaning users can copy and paste URLs to access specific routes directly.

Additionally, we learn how to programmatically interact with the history object to move forward or backward through the navigation stack, enhancing the user experience by providing full control over navigation actions.

This compatibility with the native history API ensures that TanStack Router applications behave similarly to traditional websites, offering a seamless and intuitive user experience.

Browse History in Tanstack Router

Browse history in TanStack React Router using the native history API for seamless navigation

In this lesson, we explore how to hook into TanStack Router's lifecycle hooks to execute custom logic during route changes.

The hooks we'll look into are: `onEnter`, `onStay`, and `onLeave`, which are triggered when entering, staying within, or leaving a route, respectively.

All hooks receive a detailed match parameter, providing information about the route's path, ID, and tons of other details.

This allows for the implementation of features like animations or logging when navigating between routes.

We also learn how to use these hooks to track and manage state changes as users interact with the application, making it easier to implement complex behaviors based on route transitions.

Hook into Route Lifecycle Hooks in Tanstack Router

Hook into TanStack React Router's lifecycle hooks for custom route logic and animations.

In this lesson, we learn how to handle not found errors in TanStack Router by using the `notFoundComponent` at both nested and global levels.

To trigger the display of a `notFoundComponent`, we must throw a specific error using the `notFound` function within a loader or other lifecycle method of a route. This approach allows us to provide custom error messages for specific routes or globally across the application.

We explore how to define a notFoundComponent within a specific route's configuration and how to set a `defaultNotFoundComponent` at the router global level, which applies to all routes unless overridden locally. This flexibility ensures that users receive meaningful feedback when encountering non-existent routes.

Provide NotFoundComponent at Nested Route or Global Level in Tanstack Router

Handle notFound errors in TanStack Router with notFoundComponent at nested or global levels.



In this lesson, we learn how to access dynamic route parameters using the `useParams` hook in TanStack Router.

When used with a specific `Route` object, `useParams` provides type-safe access to route parameters, ensuring that TypeScript knows the exact types of these parameters.

This approach eliminates the possibility of undefined/optional values, making it safer for accessing parameters like `employeeId`.

However, when using `useParams` globally without specifying a route, it requires an options object with `{ strict: false }`, which reduces type safety.

In this case, the hook can access parameters from any route in the application, but it does not guarantee their existence or type. This flexibility allows components to be reused across different routes, but it requires careful handling of potential errors.



Access Dynamic Route Parameters with useParams in Tanstack Router

Access dynamic route parameters with useParams in TanStack React Router for type-safe routing.

In this lesson, we learn how to reorganize file-based routes in TanStack Router to accommodate nested routing structures.

We explore how to create additional nested routes by converting files into directories, allowing for further nesting.

For example, to create a nested route like `/employees/$employeeId/edit`, we can create a **directory** (!) named `$employeeId` and place an `index.tsx` file inside it to define the route component for this nested route.

This approach provides flexibility in organizing files while maintaining the convention that file names and locations align with route paths. We also see how to adapt existing components and loaders to work with these reorganized routes, enabling features like edit forms or delete actions (or whatever) within nested routes.


Reorganize File-Based Routes in Tanstack Router

Reorganize file-based routes in TanStack Router for flexible nested routing.



In this lesson, we learn how to parametrize the loader for a nested route in TanStack Router.

We focus on a nested route like `/employees/$employeeId`, where the `$employeeId` is a **dynamic parameter**.

To fetch data for this route, we use a `loader` function that accesses the `$employeeId` parameter. This is achieved by using the params object available in the `loader` function, which contains the dynamic segments of the URL. We then use this parameter to call a function like `getEmployeeById`, which fetches specific employee details from an API.

We highlights that TanStack Router **automatically infers types** for these parameters, ensuring type safety for nested routes.

Parametrize Route Loader for Nested Route in Tanstack Router

Parametrize nested route loaders in TanStack Router using path parameters

In this lesson, we learn how to create nested routes and outlets in TanStack Router using file-based routing.

We start by creating a new `employees` directory and files to represent nested routes, such as `/employees/$employeeId`. The `$` symbol is used to denote dynamic parameters.

We then use the `<Link>` component from TanStack Router to create links to these nested routes, passing necessary parameters.

To render the nested content, we use the `<Outlet>` component (nested), which automatically renders child routes. This approach allows us to dynamically display stuff under a nested route.

All the time, the TanStack Router generator automatically updates the route tree based on file changes - our routing configuration remains consistent 🔥



Create Nested Route and Nested Outlets in Tanstack Router

Create nested routes and outlets in TanStack Router using file-based routing

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