Learn Elasticsearch, Go and Nightmare

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

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 is an open source programming language that makes it easy to build simple, reliable, and efficient software. It is used frequently in the container ecosystem by projects such as Kubernetes (container orchestration), Docker (containers), and Cilium (BPF networking).

This playlist is a collection of videos that will start you off on your Golang journey.

Golang from Scratch

In this course, you will learn the basics of using Elasticsearch within your application. You will learn how to store and retrieve data in Elasticsearch as well as how to leverage its powerful search features.
 
You will be able to design indices, types and maps for your application to leverage the most from Elasticsearch and you will learn how to monitor the health and performance of your Elasticsearch servers to identify and resolve capacity issues before they impact your application.

Throughout this course, we will be using the [Simpsons dataset](https://www.kaggle.com/wcukierski/the-simpsons-by-the-data) containing all of the Simpsons episodes, characters, and lines. It will be the foundation for learning to retrieve data from Elasticsearch, perform complex searches, and understand and implement best practices for storing data in Elasticsearch. 

elasticsearch

Get Started with Elasticsearch

We'll cover a small Golang program that prints a string to the terminal, showing how to set up an executable program, import a package, and build a binary.

Getting Started with Hello World in Go

Returning multiple values from a function is a common idiom in Go, most often used for returning values along with potential errors. We'll go over how to return multiple values from a function and use those values in our program.

Returning Multiple Values from a Function in Go

Functions are as useful in Go as many other programming languages. In this lesson we write a function that operates on numbers covering the func keyword, argument and return signatures, and writing the function body.

Writing a Function that Multiplies a Number by Two in Go

Golang has testing tools built into the standard go tool and the standard library. Here is how to write a unit test on a function so that you can run it with `go test`.

Writing a Unit Test in Go

iota is a constant generator that can be used to construct enums. It is effectively an infinite list that starts at 0 that can be used to produce a value for a set of constants.

iota, The Golang Constant Generator

Constants are expressions whose values are known at compile time, which means that we can generate errors for expressions using those constants at compile time as well, instead of runtime.

Golang Constants Basics

Golang includes the `go mod` command to initialize a new project. Sometimes that command fails even though it tries to be smart about where to get the name of your module from so we give an example of how to explicitly set the name of your go modules based project.

```shell
mkdir my-go-project
cd my-go-project
go mod init github.com/christopherbiscardi/my-go-project
```

Initializing a project using Go modules

Golang has no built-in function(s) to filter an array. This lesson will teach you two different ways to filter.

The first is to create a separate array and add the filtered elements to it. This works great, but doesn't use memory as efficiently as the second way.

The second way shows you how to filter by altering the original array in place without making another array to hold the filtered elements. But, it has a side-effect that I'll tell you about which may help you decide which approach you will use to filter your array. 

Filter an Array in Go

There are numerous ways that you can declare and create arrays and slices in Go. This lesson will show you several and I talk about the advantages and disadvantages of one over another. After watching, you will better understand all of the possible ways you can declare/create as well as the idiomatic way.

These include:

* var
* the built-in function *new*
* the built-in function *make*
* Array and Slice literals

While it is not the main intent of this lesson, I do touch on some of the differences between slices and arrays.

Checkout the code in my [github repo](https://github.com/JeffBNimble/GoLessons/tree/master/Array-Declare).

Declare Arrays and Slices in Go

There is a built-in append function that is used to append elements to a slice. We'll see in this lesson that the append function works only with slices, not arrays. There are also some nifty alternate uses of the the append function that make appending super easy.

Checkout the sample code in my [github repo](https://github.com/JeffBNimble/GoLessons/tree/master/Array-Add).

Append Elements to 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

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 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 

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

*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

*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*

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

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