DEV Community: Zack

Asynchronous Programming in Node

Zack — Sun, 08 Dec 2019 20:49:31 +0000

Hello, everyone! I thought I'd go over a pretty interesting topic, which is asynchronous programming.

The programming language we'll be using is JavaScript (Node), of course.

An Explanation

The setTimeout function in JavaScript calls a function after a certain amount of time in an asynchronous fashion. We're going to use this inbuild function to our advantage.

Let's first create a wrapper function:

let wrapper = function(func) {
    setTimeout(func, 0);
}

Nice, so all we need to do now is to call the function with a function as the first argument:

let wrapper = function(func) {
    setTimeout(func, 0);
}

wrapper(() => console.log('Hello, world! (1)'));
console.log('Hello, world! (2)');

Now if you run it, the output should be like this:

Hello, world! (2)
Hello, world! (1)

Why is Hello, world! (2) shown first? It's because of the way JavaScript works; it prioritizes non-asynchronous code in the event loop.

There's a great video by Fireship that explains it a bit better: link

An Online Multiplayer Game Example

Zack — Tue, 29 Oct 2019 02:43:43 +0000

Hey everyone! It's been a little while, but here I am with a new project: a simple game server made entirely with Node.

Source code and docs here.

Let's go over the server script:

./server.js

// HTTP Server

var express = require("express"); // Load the express package
var app = express(); // Create an app with express
var up = true; // Unused value... I'll remove it in the future.
var data = { // The cube's data.
    x: 0, // "X" position of the cube.
    y: 0 // "Y" position of the cube.
};

app.get("/updatePos", (req, res) => { // Create a listener for /updatePos
    res.json(data); // Return the cube's data.
});

app.get("/setPos/:x/:y", (req, res) =>  { // ^
    data.x = parseInt(req.params.x); // Sets the "X" position
    data.y = parseInt(req.params.y); // Sets the "Y" position
    res.status(200); // Sets the result status as a success
    res.json({data: "Hello, world!"}); // Just so it returns something.
});

app.listen(8080, () => { // Start listening.
    console.log("Hosted server at localhost:8080"); // Let the user know the server started
});

I explained each line of code briefly with comments so you can understand it a bit better. Also, don't forget to read the readme.md file so you know it's dependencies.

Have a nice day! :D

Just a Quick Thank You <3

Zack — Wed, 28 Aug 2019 21:12:54 +0000

<?php
echo "Thanks for 40 Followers!"

A Better Explaination

Zack — Mon, 19 Aug 2019 21:12:44 +0000

Hello, again!

Since my previous post on Snippet was vague, I decided to make a new one, describing what it is for and what possibilities it could have.

A Description of Snippet

(Issue Link) So, you found Snippet. What can you use it for?

It's like Github's Gist, but it's completely offline unless you are updating the library.

It's updated every day to make sure everything is working!

It has a variety of "snippets" in multiple programming languages, see Supported Languages

Example Real-World Usage

Let's say you are looking for an example of, (for this example) how to write a string in C.

(There probably are multiple tutorials for this online!) You can't find anything online, but you heard of a Node.JS package called "Snippet". It has code examples in multiple programming languages such as Javascript, Java, C (C# and C++ as well), Python and more.
You check it out, in the snippets folder, you see a folder called c, open it and boom; you found a certain hello_world_c.c script.

It's exactly what you are looking for! Now you can cherish this simple piece of code in your heart, or you can use it.

Installation

Check out this post or use the command:

npm install @matrixoc/snippet

Or get it from GitHub, if you don't want to use the download feature, use the commands:

git remote add origin https://github.com/opensource-matrix/snippet.git
git pull

Supported Languages

AS OF THIS POST

C

C#

C++

JavaScript/Node

Ruby

Crystal

Python

HTML

Batch

Shell

Java

It's super easy to add a language, let's look into it here!

Creating A Language

Create a new folder in snippets with the name of the programming language.
Run the command `node addLanguage [language name] [language file extensions (separated by spaces]

So for example, to add Objective-C, we could do:
node addLanguage objective-c .objc .m

Conclusion

If you have any questions at all, create an issue, or check out this issue, and that's about it, thanks for reading!

If you want to contribute, go to the GitHub repository, linked here, thanks to the contributors who helped!

Calculating the Possible Rubik's Cube Combos

Zack — Sat, 17 Aug 2019 23:38:03 +0000

Hello everyone!

Today I will show you how you can calculate how many Rubik's cube combinations there are.

(This works on both web and Node!)

The correct output is at the end of the post :)

We'll start by making a function in our Javascript file, let's call it calc.

function calc() {
}

Make sure to give it two arguments, x and y, just like so:

function calc(x, y) {
}

Now, inside of this function, define a variable called j.

function calc(x, y) {
  var j = 0;
}

We'll use this variable as the output from the function, so calc(1, 1) would output y, which would be equal to 1.

Make your for loop. It will help us calculate the value.

function calc(x, y) {
  var j = 0;
  for(var i = 0; i < y; i++) {
  }
}

In our forloop, it does 3 things (in order):

defines the initial i variable.
makes sure i is less than y.
adds one to i.

That's great, now add an if-else statement that checks if j is equal to 0.

function calc(x, y) {
  var j = 0;
  for(var i = 0; i < y; i++) {
    if(j == 0) {
    } else {
    }
  }
}

Why are we doing this?

The formula is that j is set to j * x for y times. It will always be 0 if we don't set that initial value.

Let's finish up our function!

function calc(x, y) {
  var j = 0;
  for(var i = 0; i < y; i++) {
    if(j == 0) {
      j = x;
    } else {
      j = j * x;
    }
  }
}

Absolutely DON'T forget to return the value of j after that for loop!

function calc(x, y) {
  var j = 0;
  for(var i = 0; i < y; i++) {
    if(j == 0) {
      j = x;
    } else {
      j = j * x;
    }
  }
  return j;
}

Okay, what now!?

So how do I sum up the number of possible combinations of Rubik's cube with this function?

There are 6 sides to a Rubik's cube; each with a different color. Each side has 9 tiles, with 6 possible colors.

We'd work it out like this:

calc(calc(6, 9), 6);

Just print it out to the console with console.log, your code should look like this:

function calc(x, y) {
  var j = 0;
  for(var i = 0; i < y; i++) {
    if(j == 0) {
      j = x;
    } else {
      j = j * x;
    }
  }
  return j;
}


console.log(calc(calc(6, 9), 6));

It will output this:

> 1.0475325355943345e+42

That is our answer, 1.0475325355943345e+42.

Thanks for reading everyone! <3

NEW NODE PACKAGE

Zack — Sat, 17 Aug 2019 20:31:58 +0000

Hello, all!

My name is Zack, I am a developer that has been working on this package since it started. (I created it!)

It's a source for a whole bunch of code "snippets" that are free to use anywhere, anytime. Snippet is supposed to be as crowd-sourced as possible, so contribute your code snippets at our Github:
Github Link

It has an easy to use API that allows instant access to any snippet.

Usage

There is a few functions that package up some helpful methods for use with Snippet.

/* Load up the Node module */
const snippet = require('@matrixoc/snippet');

Get All Snippets

snippet.getSnippets();

Get All Snippets for a Certain Language

snippet.getSnippetsByLanguage('javascript');

Get a Snippet By Name

snippet.getSnippetByName('hello_world_js');

Check If a Snippet Exists

snippet.checkName('hello_world_js');

Check If a Language Has Any Snippets

snippet.checkLanguage('javascript');

Installation

You can download from NPM, Yarn or RubyGems.

npm i @matrixoc/snippet
yarn add @matrixoc/snippet
gem install snippetpkg