Learn Chai, Nginx and Script-kit

How often do you avoid scripting something because it takes too much effort?\n\nScript Kit makes it easy to create and run scripts that solve your daily problems. Create a new script from the prompt then your script opens in the editor of your choice. Write a few lines of JavaScript. Then run the script from the prompt.\n\nSimply put, Script Kit helps you script away the friction of your day.

script-kit

Create, read, update, delete. Four actions that every developer becomes intimately familiar with over their career. Script Kit aims to make this process as pleasant as possible using a `db` helper and what better way to show it off than a Todos app?

You will also learn how to create and switch between tabs through Script Kit's `onTab` and `setTab` methods. 

[Install todos](https://scriptkit.com/api/new?name=todos&url=https://gist.githubusercontent.com/johnlindquist/3bdc967ffbd2f6d72491d07bf720f7e2/raw/a37b0058b502d6ba4bebd7a31a30be8789f5a146/todos.js")

```js
// Name: Todos

import "@johnlindquist/kit"

let { todos, write } = await db({ todos: [] })

onTab("Todos", async () => {
  while (true) {
    let todo = await arg("Toggle todo:", todos)
    let t = _.find(todos, todo)
    t.tag = t.tag === "open" ? "done" : "open"
    await write()
  }
})

onTab("New", async () => {
  let name = await arg("New todo:")
  todos.push({ name, id: uuid(), tag: "open" })
  await write()
  setTab("Todos")
})

onTab("Remove", async () => {
  let todo = await arg("Remove todo:", todos)
  _.remove(todos, todo)
  await write()
  setTab("Todos")
})
```


Build a Multi-Tab Todos App in Script Kit

When you want to collect news sources, airline ticket prices, or any events from sites that don't offer APIs, you can use scrapers to grab elements from off the page. 

Script Kit includes a `scrapeSelector()` helper that takes the URL you want to scrape and the selector you want from the page. Using the `// Schedule` metadata, you can also have this script run in the background on a Chron schedule and collect the data for you.


[Install scrape-tech-news](https://scriptkit.com/api/new?name=scrape-tech-news&url=https://gist.githubusercontent.com/johnlindquist/acd397a2ed487ef2a06c00d2951bed63/raw/3942107d2c92abc2c0317d15b0b3d025c5643ef0/scrape-tech-news.js")

```js
// Name: Scrape Tech News
// Schedule: 0 11 * * *

import "@johnlindquist/kit"

let h3s = await scrapeSelector(
  "https://news.google.com/topics/CAAqJggKIiBDQkFTRWdvSUwyMHZNRGRqTVhZU0FtVnVHZ0pWVXlnQVAB?hl=en-US&gl=US&ceid=US%3Aen",
  "h3"
)

let filePath = home("tech.md")
await ensureFile(filePath)
let contents =
  `

## ${new Date()}

` + h3s.map(h3 => `### ${h3}`).join("\n")
await appendFile(filePath, contents)
```

Scrape a Website on a Schedule with Script Kit

We put a lot of work into browsing the internet every day, it would be a pity to lose it all by closing all of our tabs. 

Script Kit can collect all of the tabs you currently have open in Chrome using its `getTabs` method and store them anywhere you want. 

This particular script converts the tabs to markdown links and stores them in a text file on your file system, but you could convert and store them using any approach you can think of.


[Install save-tabs](https://scriptkit.com/api/new?name=save-tabs&url=https://gist.githubusercontent.com/johnlindquist/4713a161a9ec48932b05436ba6a1a123/raw/33f753586d1a158dfb69d07f29850b6013d59f8b/save-tabs.js")

```js
// Name: Save Tabs

import "@johnlindquist/kit"

let tabs = await getTabs()

let tabsMd = tabs
  .map(tab => `* [${tab.title || tab.url}](${tab.url})`)
  .join("\n")

let notes = await editor(tabsMd)

let filePath = home("tab-notes.md")
await ensureFile(filePath)
await appendFile(filePath, notes)

edit(filePath)
```


Save Chrome Tabs in a Markdown File and Take Notes with Script Kit

Sometimes you just want to select and modify some text you have written somewhere on your system. To help you with this, Script Kit provides a `getSelectedText` and `setSelectedText`. Between these two helpers, your script and use and/or modify the text however you want. 

Applying an npm tool like `title-case` can help when you're not entirely sure when certain words need to be capitalized. In fact, I used the title case script on the title of this lesson!

[Install title-case](https://scriptkit.com/api/new?name=title-case&url=https://gist.githubusercontent.com/johnlindquist/0f8323d6aa599cfd62034351f9d38e8c/raw/625d0afd57ccbf8bf64c62bd135474cecf98c58b/title-case.js")

```js
// Name: Title Case

import "@johnlindquist/kit"

let { titleCase } = await npm("title-case")

let selectedText = await getSelectedText()
let titleText = titleCase(selectedText)

await setSelectedText(titleText)

// This Is the Title of My Next Blog Post
```


Apply Title Case to Text Anywhere Using Script Kit

Developers often keep their dev projects in a specific directory like "dev", "projects", or something similar. Script Kit allows you quickly read all the files of any directory then display them in a list so you can open them in your editor.


[Install open-project](https://scriptkit.com/api/new?name=open-project&url=https://gist.githubusercontent.com/johnlindquist/91cf994e450ecd5d45bce9aef9b345a1/raw/880be2d827b9602afe59d4e230e6753288f5bbb8/open-project.js")

```js
// Name: Open Project

import "@johnlindquist/kit"

let dirs = await readdir(home("dev"))

let selectedDir = await arg(
  "Open Project:",
  dirs.map(dir => ({
    name: dir,
    description: home("dev", dir),
    value: home("dev", dir),
  }))
)

edit(selectedDir)
```

List and Launch Dev Projects with Script Kit

We all have various tasks we need to accomplish with images. Whether it's resizing, optimizing, organizing, uploading, or anything else. Script Kit provides a `drop` component so you can simply drag and drop images into a script and process them in whatever way matches your workflow.


[Open drop-image in Script Kit](https://scriptkit.com/api/new?name=drop-image&url=https://gist.githubusercontent.com/johnlindquist/fe5b06f81cfea0d2dd94f743bc40ed15/raw/40a1b6ab271f7f664d7e54c4b779b056c6195b1c/drop-image.js")

```js
// Name: Drop Image

import "@johnlindquist/kit"

let files = await drop()
let imagePath = files[0].path

let Jimp = await npm("jimp")

let image = await Jimp.read(imagePath)
let newImagePath = path.resolve(
  path.dirname(imagePath),
  `new-${path.basename(imagePath)}`
)
await image
  .resize(parseInt(await arg("Width:"), 10), 100)
  .write(newImagePath)

```


Manipulate Images With Drag and Drop in Script Kit

Chrome allows developers to execute JavaScript using Apple Events. When you enable this feature, you can write scripts that can access and modify the page you're currently browsing. 

You can get the site's contents, update storage, or do any action you would typically do through an extension of the Chrome Dev Tools.

```jsx
let value = await applescript(`
tell application "Google Chrome" to tell window 1
	get execute active tab javascript "

${js}

"
end tell
`)
```

Control Chrome From Script Kit using Apple Events

Many developers use Chrome's Dev Tools as a playground for testing out data and JavaScript features. Script Kit enables you to launch Chrome Dev Tools instantly by simply using the `dev` method. Any data you pass into `dev` will show up in the console so you can inspect and play with the data in any way that you want.

[Install dev-tools-demo](https://scriptkit.com/api/new?name=dev-tools-demo&url=https://gist.githubusercontent.com/johnlindquist/6dcaf61e92819114c7478fefd24a71f8/raw/c2e69bfcff581f7929b881638627201b549d23f1/dev-tools-demo.js")

```js
// Name: Dev Tools Demo

import "@johnlindquist/kit"

let response = await get(
  `https://api.github.com/users/johnlindquist/repos`
)
dev(response.data)
```


Instantly Launch Chrome Dev Tools with Script Kit

This lesson walks through a script that can query a Hacker News API and display the information in Script Kit. 

Learn to do several things using Script Kit's global API methods, such as how to make and inspect data requests using `get` and `inspect`, how to display lists of data using `arg`, and how to display previews of the current selection.

[Install Hacker News Script](https://scriptkit.com/api/new?name=hackernews&url=https://gist.githubusercontent.com/johnlindquist/8728c8f56dd88951127810f0dea818d2/raw/8be4d28aa695f7842b610be258db7cd2e823a239/hackernews.js)

Write a Script with Script Kit to Browse Hacker News

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

node

Ghost has two hard dependencies which need to be installed before it can run. Those are Nginx and Node.js.

We will start by installing Nginx and set Nginx up to control the traffic coming into the EC2 server. After this, we'll install NVM using the raw install script that they provide on GitHub. With NVM installed we can then install the latest version of Node.js


Install Nginx and Node.js on a AWS EC2 Server

NGINX is a free, open-source, high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server. 

nginx

Node.js apps built with Docker cannot scale horizontally by themselves. In this lesson we will spawn out multiple Node.js processes/containers, and move the incoming request handler to an Nginx proxy to load balance and properly scale our Node.js app.

Scale Docker Horizontally with Nginx Load Balancing

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

chai

In this lesson, you will learn how to verify your API server is returning HTTP 400 responses when clients submit incorrect data. Returning HTTP 400 ensures that your clients are notified of the incorrect usage. Testing for them ensures your API returns errors instead of incorrect responses when supplied with incorrect data.

Test for HTTP 400 responses with Mocha and Chai

In this lesson, we will use Chai's request method to test our Node application's API responses.
By the end of this lesson, you will know how to:
- install the prerequisites to use mocha and chai in your application
- test for HTTP status response codes
- test for a string of text on a page
- test for a json response and validate the properties of the object
- write tests that not only verify the response of your application, but the behavior as well


Test Node RESTful API with Mocha and Chai

Learn how to setup an Nginx proxy server with Docker that sits in front of a Node.js app. You can use a proxy to control the flow of frontend requests hitting your app, as well as to achieve better performance and scalability. We'll create a sample Node.js app, configure a default Nginx configuration file for proxying web requests, build both Node.js and Nginx Docker images, and learn how to link everything up and get it running with Docker specifics.

Setup an Nginx Proxy for a Node.js App with Docker

Learn about the concepts of managing data within Docker volumes, including all of the commands to create and manage volumes. We'll demonstrate how to mount a Docker volume to one or many containers by creating and mounting a volume to an Nginx proxy, and then verify the output with curl. You'll also see how changes to files within volumes of one container propagate to other containers with the same volume mounted, and learn various commands to inspect Docker volumes.

Manage Data within Docker Volumes

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. Mocha tests run serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases.

mocha

Writing great ES6 style Promises for Node.js is only half the battle. Your great modules must include tests as well to ensure future iterations don't break them. In this lesson, I show you a simple ES6 Promise in Node.js, then walk you through creating tests in Mocha using chai and chai-as-promised to test both resolve and reject methods.

Testing ES6 Promises in Node.js using Mocha and Chai

Now that you've got everything set up with mocha and chai, it's time to actually write tests. In this lesson you'll learn how to use `describe` and `it` to outline your tests and make sure you don't break your library in the future.

Unit Testing with Mocha and Chai

Every dependable library needs to have tests to ensure that you don't push accidental bugs. In this lesson, see how you can set up mocha and chai to start testing your library.

Setting up Unit Testing with Mocha and Chai

Scripting can save you a _ton_ of time by automating your daily workflows.

But it's hard to justify the time investment of learning Bash to write your scripts.

Bash is the great barrier we all face when trying to script away our daily tasks. There are some common problems that we run into when dealing with it. Like what if we want to display images? Or share our script with other devs _cross platform_? 

You know what you want your script to do. You know you could figure it out if you had the time. But it's all just too darn much.

What if you could write your scripts in JavaScript, launch a GUI, and were actually *easy* to share with your team? **audible gasp**

Script Kit is the tool that’s been missing from your developer toolbox for so, so long. 🛠

![word-api.gif](https://res.cloudinary.com/dg3gyk0gu/image/upload/v1639684537/course-resources/script-kit-cook-book/word-api.gif)

**Download the new hotness here: [https://scriptkit.com](https://scriptkit.com/) 🔥**

We even use Script Kit internally at [egghead.io](http://egghead.io) to manage our lesson transcripts! With a single script, we query an API to list the transcripts, modify them as necessary, then post the changes.  

**This course was made to show you what Script Kit can do for you.** 

John Lindquist, the creator of Script Kit and co-founder of egghead.io, has put together this series of lessons to give a quick overview of the features of Script Kit to help you get oriented. 

We know you’ll be off and having a blast with your own scripting ideas in no time!

Script Kit Showcase for Optimizing Your Everyday Workflows



Discover how to harness the power of Cursor IDE's Composer Agent feature to optimize your code. In this lesson, you'll witness an AI agent doing all the work to generate test suites, implement performance benchmarks, and create optimized function variations - all without writing a single line of code. You'll learn how to validate performance improvements through data-driven benchmarking, ensuring that optimizations are backed by concrete metrics rather than speculation. This hands-on demonstration showcases a groundbreaking approach to automated function development that combines the precision of test-driven development with the efficiency of AI-powered optimization.


Agent-Driven Development in Cursor: Testing, Benchmarking, and Optimizing Functions

This course is aimed for using `zod` effectively in projects based on TypeScript (both browser and node.js). The benefits you gain with this course is not just simply coding, but also understanding when/why/how should you perform runtime validation.

`zod` is the missing piece to TypeScript's capabilities, which can guarantee type-safety only in compile-time.

`zod` can be used whenever the compiler cannot guarantee what happens in runtime. And... it's a very frequent usecase, such as HTTP calls, websockets, etc.

In this course you get quickly up and running by:
1. using `zod` with primitives and objects
2. adapting `zod` quickly to existing projects thanks to automatic generators
3. changing the strategy frm type-first to schema-first
4. using error-throwing `parse` or non-error-throwing `safeParse` basing on your needs
5. applying `zod` to the most common usecase - validating API responses
6. handling errors the most convenient way (out of many!)

Take advantage of runtime validation with `zod`. Take advantage of the detailed lessons in this course 🔥

Effective Runtime Type Checks with Zod


Cursor can now automatically run commands in the terminal and walk step-by-step towards building out your entire project. You give it a goal, then it will suggest the commands you need to run and the files that you need to create and you can work with it to achieve what you're building. This lesson does a quick walkthough of using a Cursor Agent to build a project from scratch and guide it along the way. Cursor Agents definitely feel like a sneak peek at the future of programming!

Cursor Agents Initial Impressions - Allow an AI to Build Your Entire Project

Mock Service Worker is an API mocking library that allows you to write client-agnostic mocks and reuse them across any frameworks, tools, and environments.



Mocking WebSocket APIs with Mock Service Worker


While using anonymous functions might seem convenient, they can create difficulties when trying to identify performance bottlenecks during profiling. This lesson will demonstrate how named functions make it easier to pinpoint and address performance issues, ultimately leading to more efficient and debuggable code. Learning this practice will greatly improve your ability to locate and fix performance issues in complex projects.

Always Name Functions in JavaScript


When attempting to load the same module twice in JavaScript you'll hit a cache and code won't re-run. In scenarios where you actually do want to have state in your modules, you'll have to use a cache-busting technique by passing a query parameter to a dynamic import. This lesson walks through how to add a query parameter, how to add the appropriate types for loading dynamic modules in TypeScript, and when these techniques are valuable.

Import the Same JavaScript Module Multiple Times with Cache Busting



The include keyword in GitHub Actions empowers you to add custom variables to your matrix strategy, providing flexibility beyond standard configurations. In this video, we'll explore how include allows you to define specific combinations of variables, enhancing control over your workflow runs. You'll see how this feature enables you to tailor jobs for unique environments or scenarios not covered by the default matrix options. By leveraging include, you can efficiently manage complex build processes with greater precision. This technique helps you streamline your CI/CD pipeline, making it more adaptable to your project's evolving needs.

Use GitHub Actions Matrix Include for Complex Job Configurations

While running `zod` schema validation agains domain-rich objects, the error message saying that _a string is not a number_ might not be really useful.

Especially, when you need to provide a meaningful feeback to the user, e.g. after they have submitted a form with lots of data.

`zod` allows to customize messages on a very granular level. We can also extract repeatable customization to `zod` error maps.

Finally, in order to process an error message further (e.g. display it to the user), we need to handle the `zod` validation errors effectively. Especially, when a big object validation has failed and we could receive a handful of errors.

That's what we learn in this lesson. 🔥

Customize zod Error Messages and Handle zod Errors Effectively

customize zod validation messages, customize zod schema property messages, reuse error maps across different schemas, navigate through zod error objects

You might want to run `zod` schema checks in different styles.

Sometimes you prefer to conditionally throw the error - that's what `parse` does. But another time you'd prefer to receive a `boolean` property that determines whether the validation was successful or not - and perform further actions accordingly.

Additionally, the error-throwing API of `parse` works extremely well with [TypeScript assertion functions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#assertion-functions). Their combination is just... perfect! 👌

That's what we learn in this lesson.

Use parse and safeParse Runtime Type-checks with zod

use zod parse function to conditionally throw ZodError, use zod safeParse to get a boolean value and run typescript type guard over success property

In this lesson we learn that TypeScript cannot guarantee correct shapes of responses. That's due to TS performing checks in compile-time, while the response will be availbale in runtime - when TS doesn't exist anymore.

In some situations, such as HTTP requests, runtime type checks such as `zod` are essential for providing quick feedback around data-related errors.

Understand where are the possible mistakes to make while using TypeScript with HTTP calls. Use `fetch` and `axios` along with `zod` schema checks.

Also, note that similar mistakes or mistakes could happen while using web storage (e.g. `localStorage`)

Validate HTTP API Response with zod, fetch and axios

use zod as an HTTP response validation tool along with fetch and axios in order to make sure that the response has expected data structure

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