Learn Go, Jekyll and Serverless

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 video you'll learn how to deploy a React app to AWS using AWS Amplify Hosting's drag and drop folder functionality. The app will also automatically be globally distributed on AWS's global CDN.

Deploy a React App to AWS in 24 seconds

Starting from a prebuilt frontend, Jason Lengstorf guides you through the creation of a "Corgi Up-boop App" that uses Netlify Functions and Hasura. You can view [the deployed final product on Netlify](https://egghead-serverless-functions.netlify.app/).

You'll set up the Netlify CLI, and configure a local development environment before writing and deploying functions with a few different use cases.

The first example function bypasses CORS restrictions to retrieve corgi data from an example third-party API.

Next, you'll configure environmental variables to securely communicate with the Unsplash API without exposing private keys to the client.

Serverless functions don't persist data by themselves, so we will use  Hasura to create a GraphQL API for tracking the number of "boops" each corgi receives.

This course is an excellent illustration of the speed of Serverless functions, and how fast you can implement functionality in your web applications.

An all-in-one workflow that combines global deployment, continuous integration, and automatic HTTPS.

netlify

Build a Corgi Up-boop Web App with Netlify Serverless Functions and Hasura

Environment variables set in a `.env` file can be imported using the Netlify CLI with the following command: `netlify env:import`.

This allows you to manage environment variables directly on Netlify, providing the benefit of security and flexibility of sharing environment variables with your team. 

From inside Netlify, you can access the environment variables in:

`Site settings` > `Build & deploy` > `Environment` > `Environment variables`

Import and Set Environment Variables from a .env file using Netlify CLI

CORS limits websites from communicating with other domains without the full consent of both sites. Consuming data from a 3rd Party REST API makes it difficult since we can't properly configure the appropriate CORS headers. To solve this, we'll set up a proxy server to request the data using a Netlify function that avoids CORS altogether.

The Third-Party API that we'll be working with will provide the following data: `id`, `name`, `favoriteSong` for each corgi. 

[http://no-cors-api.netlify.app/api/corgis](http://no-cors-api.netlify.app/api/corgis)

We will also use `node-fetch` a light-weight module that brings the `fetch` API to fetch the data into our application.

Circumvent CORS when Accessing a Third-Party API using Netlify Functions 

There are a few ways you can run Netlify serverless functions while you are developing them. 

You can: 

- Navigate to the directory under the `/.netlify/functions/` path
- Curl them using the full URL
- Use an app like Postman

Manually Trigger Netlify Serverless Functions Locally

Netlify makes deploying to production a breeze by configuring your Netlify CLI to your Netlify account and integrating with GitHub.

We'll log in to Netlify through the CLI and initialize a site by completing all the options that the CLI runs us through. Once this is done, Netlify will trigger new builds for your site every time you push to GitHub.

Deploy Serverless Functions to Production on Netlify using the Netlify CLI

Netlify makes developing serverless functions easy with the netlify-cli (`ntl` for short). You'll be able to build and test functions locally as well as publish your functions from the CLI. 

We will install netlify-cli globally and create a `netlify.toml` file that will configure where the CLI should look to run functions that we define, in our case `functions/`. When the application is served up, Netlify runs functions under `/.netlify/functions/`.

Set up a Local Development Environment for Serverless Functions Using Netlify

A serverless function is something that is going to allow us to do server-like things without having to manage servers, but an important distinction here is that serverless does not mean that there are **no** servers. 

The environment is actually running on top of an operating system and uses physical servers, but the responsibility for provisioning and managing the infrastructure belongs entirely to the service provider.

Some of the benefits of using serverless functions: 

- **Enhanced scalability.** No need for developers to implement code to scale. It scales automatically.
- **Reduced time to market.** Serverless is an optimized set of tools for building quickly.
- **No boiler code.** A serverless function is just a tiny piece of logic. Reducing the complexity of software.
- **More time for user experience.** Serverless functions allow teams to focus resources on the user experience and not on managing servers.
- **Security.** We can call third-party APIs securely without exposing important data on the client-side.

What Are Serverless Functions?

Go is a server-side language, but today we can compile Go code to WebAssembly as well - making it possible for us to bring programs written in minimalistic Go code into the browser!

With this collection, we will learn how to compile and run Go WebAssembly programs in Node.js and the browser, and how our Go code can interop with JavaScript and manipulate the DOM. We will also talk about configuring our VS Code workspace and optimizing the Go WASM binary size.

Go is an open-source programming language that makes it easy to build simple, reliable, and efficient software.

WebAssembly with the Go Language

*Go ^1.12*

When using Go modules related to WebAssembly, namely `syscall/js`, the default settings in VS Code will trigger error reports like *"Build constraints exclude all Go files"* in the editor. In this lesson, we will learn how to fix this and improve our coding experience.

Configure Go Build Constraints in VS Code to work with WebAssembly

*Go ^1.12*

In this lesson, we will see how we can expose Go lang functions from a WebAssembly module so that we can interact with them from the JavaScript environment.

Call a Go WebAssembly function from JavaScript

*Go ^1.12*

The ability to manipulate the DOM is sometimes crucial when it comes to working with apps powered by WebAssembly. In this lesson, we will see how we can utilize Go's `syscall/js` module to interact with the DOM by porting a sample JS code snippet to Go.

Interact with the DOM using Go's `syscall/js` module

*Go ^1.12*

In this lesson, we will see how we can interact with the JavaScript environment by using Go's `syscall/js` module to call and pass values into a JavaScript function, and access variables available in JS land.

Access JS Functions and Variables from a Go WebAssembly Program

*Go ^1.12*

In this lesson, we will learn how to load and use a Go WebAssembly binary in a web app.

Manually load a Go WebAssembly binary in a browser

*Go ^1.12, TinyGo ^0.12.0, Node ^12.14.0*

The WebAssembly binaries generated by the standard Go compiler are often unnecessarily large. In this lesson, we will learn techniques to optimize Go Wasm binary size with an alternative compiler that is designed for microcontrollers - TinyGo.

Optimize Go WebAssembly binary size with TinyGo

*Go ^1.12, Node ^12.14.0*

Compiling Go programs to WebAssembly does not require Emscripten, and the process is pretty straight forward. In this lesson, we will learn how to compile a simple Go program to a WebAssembly binary, then execute it with Node.js.

Compile and execute a Go WebAssembly program with Node

There are numerous ways to sort slices in Go.

In this lesson, we will take a quick look at an easy way to sort a slice of structs or primitives. We will learn about using one of the handy built-in functions in Go's sort package called *sort.Slice*. This function takes a slice to sort as an argument and a *less function* or *less func* for short as the second argument. You will write this *less function* to sort the slice however you wish.

Go's sort.Slice function looks like this: *sort.Slice(someSlice, func(i, j int) bool)*. It's super-easy to write an anonymous *less function* to sort.

As you will see, it's easy to use this *less function* to do simple and even complex sorts of your structs with minimal effort.

Sort Slices of Structs using Go sort.Slice

There are numerous ways to sort slices in Go.

The simplest way uses some basic built-in functions from Go's **sort** package to allow you to easily sort slices of primitives, that being **Strings**, **Ints** and **Float64s**. Using these sort functions, we don't have control over the sort order as the data will be sorted in ascending alphabetical (for strings) or ascending numerical (for Ints and Float64s) order.

In this lesson, we will take a quick look at the easiest way to sort slices of primitives. We will learn about using some of the handy built-in functions in Go's sort package, including:

* sort.Strings: Sorting a slice of strings
* sort.Ints: Sorting a slice of ints
* sort.Float64s: Sorting a slice of float64s

Sort Primitives (strings, ints, and floats) in Go 

This collection of lessons will cover a variety of topics that teach you how to work with slices and arrays in go. You'll learn how to declare them, create them using literal syntax, iterate over them, add to them, remove from them and other useful things.

Learn about slices and arrays in Go

Go has a special indexing syntax that forms the basis of removing one or more elements from a slice. I will teach you this syntax and show you its various forms.

Based upon that, I'll show you how to remove a single element from a slice. However, you may find this somewhat limiting. I also will show you a more typical example of removing elements from a slice as we iterate over it. This technique shows you how to remove multiple elements from a slice.

Remove Elements from a slice in Go

There are a couple of different ways to iterate over an array or slice in Go. The primary approach is to use range, which handles the iteration for you. However, you can also use a traditional for loop if you need to do something out of the ordinary, like iterating in reverse or skipping every other element.

Iterate over an Array or Slice in Go



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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