Code a SIMPLE Currency Converter with JavaScript && Learn Async/Await

So here's an excellent project for you to show off your skills in working with APIs but also to demonstrate your knowledge of the async and await keywords in JavaScript and how these can be used in place of Promise chains.

https://www.youtube.com/watch?v=CPO5Whz6OzM

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How to Use Hotwire Rails

Introduction

We are back with another exciting and much-talked-about Rails tutorial on how to use Hotwire with the Rails application. This Hotwire Rails tutorial is an alternate method for building modern web applications that consume a pinch of JavaScript.

Rails 7 Hotwire is the default front-end framework shipped with Rails 7 after it was launched. It is used to represent HTML over the wire in the Rails application. Previously, we used to add a hotwire-rails gem in our gem file and then run rails hotwire: install. However, with the introduction of Rails 7, the gem got deprecated. Now, we use turbo-rails and stimulus rails directly, which work as Hotwire’s SPA-like page accelerator and Hotwire’s modest JavaScript framework.

What is Hotwire?

Hotwire is a package of different frameworks that help to build applications. It simplifies the developer’s work for writing web pages without the need to write JavaScript, and instead sending HTML code over the wire.

Introduction to The Hotwire Framework:

1. Turbo:

It uses simplified techniques to build web applications while decreasing the usage of JavaScript in the application. Turbo offers numerous handling methods for the HTML data sent over the wire and displaying the application’s data without actually loading the entire page. It helps to maintain the simplicity of web applications without destroying the single-page application experience by using the below techniques:

Turbo Frames: Turbo Frames help to load the different sections of our markup without any dependency as it divides the page into different contexts separately called frames and updates these frames individually.
Turbo Drive: Every link doesn’t have to make the entire page reload when clicked. Only the HTML contained within the tag will be displayed.
Turbo Streams: To add real-time features to the application, this technique is used. It helps to bring real-time data to the application using CRUD actions.

2. Stimulus

It represents the JavaScript framework, which is required when JS is a requirement in the application. The interaction with the HTML is possible with the help of a stimulus, as the controllers that help those interactions are written by a stimulus.

3. Strada

Not much information is available about Strada as it has not been officially released yet. However, it works with native applications, and by using HTML bridge attributes, interaction is made possible between web applications and native apps.

Simple diagrammatic representation of Hotwire Stack:

Prerequisites For Hotwire Rails Tutorial

As we are implementing the Ruby on Rails Hotwire tutorial, make sure about the following installations before you can get started.

• Ruby on Rails
• Hotwire gem
• PostgreSQL/SQLite (choose any one database)
• Turbo Rails
• Stimulus.js

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Create a new Rails Project

Find the following commands to create a rails application.

mkdir ~/projects/railshotwire
cd ~/projects/railshotwire
echo "source 'https://rubygems.org'" > Gemfile
echo "gem 'rails', '~> 7.0.0'" >> Gemfile
bundle install  
bundle exec rails new . --force -d=postgresql

Now create some files for the project, up till now no usage of Rails Hotwire can be seen.
Fire the following command in your terminal.

• For creating a default controller for the application

echo "class HomeController < ApplicationController" > app/controllers/home_controller.rb
echo "end" >> app/controllers/home_controller.rb

• For creating another controller for the application

echo "class OtherController < ApplicationController" > app/controllers/other_controller.rb
echo "end" >> app/controllers/home_controller.rb

• For creating routes for the application

echo "Rails.application.routes.draw do" > config/routes.rb
echo '  get "home/index"' >> config/routes.rb
echo '  get "other/index"' >> config/routes.rb
echo '  root to: "home#index"' >> config/routes.rb
echo 'end' >> config/routes.rb

• For creating a default view for the application

mkdir app/views/home
echo '<h1>This is Rails Hotwire homepage</h1>' > app/views/home/index.html.erb
echo '<div><%= link_to "Enter to other page", other_index_path %></div>' >> app/views/home/index.html.erb

• For creating another view for the application

mkdir app/views/other
echo '<h1>This is Another page</h1>' > app/views/other/index.html.erb
echo '<div><%= link_to "Enter to home page", root_path %></div>' >> app/views/other/index.html.erb

• For creating a database and schema.rb file for the application

bin/rails db:create
bin/rails db:migrate

• For checking the application run bin/rails s and open your browser, your running application will have the below view.

Additionally, you can clone the code and browse through the project. Here’s the source code of the repository: Rails 7 Hotwire application

Now, let’s see how Hotwire Rails can work its magic with various Turbo techniques.

Hotwire Rails: Turbo Drive

Go to your localhost:3000 on your web browser and right-click on the Inspect and open a Network tab of the DevTools of the browser.

Now click on go to another page link that appears on the home page to redirect from the home page to another page. In our Network tab, we can see that this action of navigation is achieved via XHR. It appears only the part inside HTML is reloaded, here neither the CSS is reloaded nor the JS is reloaded when the navigation action is performed.

By performing this action we can see that Turbo Drive helps to represent the HTML response without loading the full page and only follows redirect and reindeer HTML responses which helps to make the application faster to access.

Hotwire Rails: Turbo Frame

This technique helps to divide the current page into different sections called frames that can be updated separately independently when new data is added from the server.
Below we discuss the different use cases of Turbo frame like inline edition, sorting, searching, and filtering of data.

Let’s perform some practical actions to see the example of these use cases.

Make changes in the app/controllers/home_controller.rb file

#CODE

class HomeController < ApplicationController
   def turbo_frame_form
   end
   
   def turbo_frame submit
      extracted_anynumber = params[:any][:anynumber]
      render :turbo_frame_form, status: :ok, locals: {anynumber: extracted_anynumber,      comment: 'turbo_frame_submit ok' }
   end
end

Add app/views/home/turbo_frame_form.html.erb file to the application and add this content inside the file.

#CODE

<section>

    <%= turbo_frame_tag 'anyframe' do %>
            
      <div>
          <h2>Frame view</h2>
          <%= form_with scope: :any, url: turbo_frame_submit_path, local: true do |form| %>
              <%= form.label :anynumber, 'Type an integer (odd or even)', 'class' => 'my-0  d-inline'  %>
              <%= form.text_field :anynumber, type: 'number', 'required' => 'true', 'value' => "#{local_assigns[:anynumber] || 0}",  'aria-describedby' => 'anynumber' %>
              <%= form.submit 'Submit this number', 'id' => 'submit-number' %>
          <% end %>
      </div>
      <div>
        <h2>Data of the view</h2>
        <pre style="font-size: .7rem;"><%= JSON.pretty_generate(local_assigns) %></pre> 
      </div>
      
    <% end %>

</section>

Make some adjustments in routes.rb

#CODE

Rails.application.routes.draw do
  get 'home/index'
  get 'other/index'

  get '/home/turbo_frame_form' => 'home#turbo_frame_form', as: 'turbo_frame_form'
  post '/home/turbo_frame_submit' => 'home#turbo_frame_submit', as: 'turbo_frame_submit'


  root to: "home#index"
end

• Next step is to change homepage view in app/views/home/index.html.erb

#CODE

<h1>This is Rails Hotwire home page</h1>
<div><%= link_to "Enter to other page", other_index_path %></div>

<%= turbo_frame_tag 'anyframe' do %>        
  <div>
      <h2>Home view</h2>
      <%= form_with scope: :any, url: turbo_frame_submit_path, local: true do |form| %>
          <%= form.label :anynumber, 'Type an integer (odd or even)', 'class' => 'my-0  d-inline'  %>
          <%= form.text_field :anynumber, type: 'number', 'required' => 'true', 'value' => "#{local_assigns[:anynumber] || 0}",  'aria-describedby' => 'anynumber' %>
          <%= form.submit 'Submit this number', 'id' => 'submit-number' %>
      <% end %>
  <div>
<% end %>

After making all the changes, restart the rails server and refresh the browser, the default view will appear on the browser.

Now in the field enter any digit, after entering the digit click on submit button, and as the submit button is clicked we can see the Turbo Frame in action in the below screen, we can observe that the frame part changed, the first title and first link didn’t move.

Hotwire Rails: Turbo Streams

Turbo Streams deliver page updates over WebSocket, SSE or in response to form submissions by only using HTML and a series of CRUD-like operations, you are free to say that either

• Update the piece of HTML while responding to all the other actions like the post, put, patch, and delete except the GET action.
• Transmit a change to all users, without reloading the browser page.

This transmit can be represented by a simple example.

• Make changes in app/controllers/other_controller.rb file of rails application

#CODE

class OtherController < ApplicationController

  def post_something
    respond_to do |format|
      format.turbo_stream {  }
    end
  end

   end

Add the below line in routes.rb file of the application

#CODE

post '/other/post_something' => 'other#post_something', as: 'post_something'

Superb! Rails will now attempt to locate the app/views/other/post_something.turbo_stream.erb template at any moment the ‘/other/post_something’ endpoint is reached.

For this, we need to add app/views/other/post_something.turbo_stream.erb template in the rails application.

#CODE

<turbo-stream action="append" target="messages">
  <template>
    <div id="message_1">This changes the existing message!</div>
  </template>
</turbo-stream>

This states that the response will try to append the template of the turbo frame with ID “messages”.

Now change the index.html.erb file in app/views/other paths with the below content.

#CODE

<h1>This is Another page</h1>
<div><%= link_to "Enter to home page", root_path %></div>

<div style="margin-top: 3rem;">
  <%= form_with scope: :any, url: post_something_path do |form| %>
      <%= form.submit 'Post any message %>
  <% end %>
  <turbo-frame id="messages">
    <div>An empty message</div>
  </turbo-frame>
</div>

• After making all the changes, restart the rails server and refresh the browser, and go to the other page.

• Once the above screen appears, click on the Post any message button

This action shows that after submitting the response, the Turbo Streams help the developer to append the message, without reloading the page.

Another use case we can test is that rather than appending the message, the developer replaces the message. For that, we need to change the content of app/views/other/post_something.turbo_stream.erb template file and change the value of the action attribute from append to replace and check the changes in the browser.

#CODE

<turbo-stream action="replace" target="messages">
  <template>
    <div id="message_1">This changes the existing message!</div>
  </template>
</turbo-stream>

When we click on Post any message button, the message that appear below that button will get replaced with the message that is mentioned in the app/views/other/post_something.turbo_stream.erb template

Stimulus

There are some cases in an application where JS is needed, therefore to cover those scenarios we require Hotwire JS tool. Hotwire has a JS tool because in some scenarios Turbo-* tools are not sufficient. But as we know that Hotwire is used to reduce the usage of JS in an application, Stimulus considers HTML as the single source of truth. Consider the case where we have to give elements on a page some JavaScript attributes, such as data controller, data-action, and data target. For that, a stimulus controller that can access elements and receive events based on those characteristics will be created.

Make a change in app/views/other/index.html.erb template file in rails application

#CODE

<h1>This is Another page</h1>
<div><%= link_to "Enter to home page", root_path %></div>

<div style="margin-top: 2rem;">
  <%= form_with scope: :any, url: post_something_path do |form| %>
      <%= form.submit 'Post something' %>
  <% end %>
  <turbo-frame id="messages">
    <div>An empty message</div>
  </turbo-frame>
</div>

<div style="margin-top: 2rem;">
  <h2>Stimulus</h2>  
  <div data-controller="hello">
    <input data-hello-target="name" type="text">
    <button data-action="click->hello#greet">
      Greet
    </button>
    <span data-hello-target="output">
    </span>
  </div>
</div>

Make changes in the hello_controller.js in path app/JavaScript/controllers and add a stimulus controller in the file, which helps to bring the HTML into life.

#CODE

import { Controller } from "@hotwired/stimulus"

export default class extends Controller {
  static targets = [ "name", "output" ]

  greet() {
    this.outputTarget.textContent =
      `Hello, ${this.nameTarget.value}!`
  }
}

Go to your browser after making the changes in the code and click on Enter to other page link which will navigate to the localhost:3000/other/index page there you can see the changes implemented by the stimulus controller that is designed to augment your HTML with just enough behavior to make it more responsive.

With just a little bit of work, Turbo and Stimulus together offer a complete answer for applications that are quick and compelling.

Using Rails 7 Hotwire helps to load the pages at a faster speed and allows you to render templates on the server, where you have access to your whole domain model. It is a productive development experience in ROR, without compromising any of the speed or responsiveness associated with SPA.

Conclusion

We hope you were satisfied with our Rails Hotwire tutorial. Write to us at service@bacancy.com for any query that you want to resolve, or if you want us to share a tutorial on your query.

For more such solutions on RoR, check out our Ruby on Rails Tutorials. We will always strive to amaze you and cater to your needs.

Original article source at: https://www.bacancytechnology.com/

#rails #ruby 

Learning to Code: How to Boost Up the Process?

Let’s face it: people are impatient by nature and most likely want things to happen faster in their lives. I would apply the same to code learners. Students, when starting to learn programming, first wonder how to speed up the training and make a career as a programmer as soon as possible.

I am not the one who convinces everyone that learning to program is a lightning-fast journey — the other thing is that it is not as difficult as people think. All boils down to interest, passion, regular practice, and patience, of course. I also often recommend different online and offline resources to my students to make their learning process easier, more effective, and faster. And in this post, I will share a few tips with you.

So, How to Learn Programming Languages Faster?

These tips are not magic pills and probably won’t make you a professional developer in a week, but they will definitely make your life easier, while the learning process won’t be that intimidating, vague, and boring. Besides, following all of them together may speed up training.

So, without any further delay, let’s get to them.

Consolidate Your Knowledge by Practicing More

No matter how simple a new subject is, it still requires you to consolidate your knowledge. Starting to play with code soon after you’ve completed the next section helps you learn the given concepts faster and feel confident when writing your first line of code. Fortunately, the web is full of platforms, where you can start practicing shortly.

Let’s consider them in detail.

#coding #learn-to-code #learning #programming #learning-to-code #machine-learning

Learn JavaScript - Full Course for Beginners. DO NOT MISS!!!

This complete 134-part JavaScript tutorial for beginners will teach you everything you need to know to get started with the JavaScript programming language.
⭐️Course Contents⭐️
0:00:00 Introduction
0:01:24 Running JavaScript
0:04:23 Comment Your Code
0:05:56 Declare Variables
0:06:15 Storing Values with the Assignment Operator
0:11:31 Initializing Variables with the Assignment Operator
0:11:58 Uninitialized Variables
0:12:40 Case Sensitivity in Variables
0:14:05 Add Two Numbers
0:14:34 Subtract One Number from Another
0:14:52 Multiply Two Numbers
0:15:12 Dividing Numbers
0:15:30 Increment
0:15:58 Decrement
0:16:22 Decimal Numbers
0:16:48 Multiply Two Decimals
0:17:18 Divide Decimals
0:17:33 Finding a Remainder
0:18:22 Augmented Addition
0:19:22 Augmented Subtraction
0:20:18 Augmented Multiplication
0:20:51 Augmented Division
0:21:19 Declare String Variables
0:22:01 Escaping Literal Quotes
0:23:44 Quoting Strings with Single Quotes
0:25:18 Escape Sequences
0:26:46 Plus Operator
0:27:49 Plus Equals Operator
0:29:01 Constructing Strings with Variables
0:30:14 Appending Variables to Strings
0:31:11 Length of a String
0:32:01 Bracket Notation
0:33:27 Understand String Immutability
0:34:23 Find the Nth Character
0:34:51 Find the Last Character
0:35:48 Find the Nth-to-Last Character
0:36:28 Word Blanks
0:40:44 Arrays
0:41:43 Nest Arrays
0:42:33 Access Array Data
0:43:34 Modify Array Data
0:44:48 Access Multi-Dimensional Arrays
0:46:30 push()
0:47:29 pop()
0:48:33 shift()
0:49:23 unshift()
0:50:36 Shopping List
0:51:41 Write Reusable with Functions
0:53:41 Arguments
0:55:43 Global Scope
0:59:31 Local Scope
1:00:46 Global vs Local Scope in Functions
1:02:40 Return a Value from a Function
1:03:55 Undefined Value returned
1:04:52 Assignment with a Returned Value
1:05:52 Stand in Line
1:08:41 Boolean Values
1:09:24 If Statements
1:11:51 Equality Operator
1:13:18 Strict Equality Operator
1:14:43 Comparing different values
1:15:38 Inequality Operator
1:16:20 Strict Inequality Operator
1:17:05 Greater Than Operator
1:17:39 Greater Than Or Equal To Operator
1:18:09 Less Than Operator
1:18:44 Less Than Or Equal To Operator
1:19:17 And Operator
1:20:41 Or Operator
1:21:37 Else Statements
1:22:27 Else If Statements
1:23:30 Logical Order in If Else Statements
1:24:45 Chaining If Else Statements
1:27:45 Golf Code
1:32:15 Switch Statements
1:35:46 Default Option in Switch Statements
1:37:23 Identical Options in Switch Statements
1:39:20 Replacing If Else Chains with Switch
1:41:11 Returning Boolean Values from Functions
1:42:20 Return Early Pattern for Functions
1:43:38 Counting Cards
1:49:11 Build Objects
1:50:46 Dot Notation
1:51:33 Bracket Notation
1:52:47 Variables
1:53:34 Updating Object Properties
1:54:30 Add New Properties to Object
1:55:19 Delete Properties from Object
1:55:54 Objects for Lookups
1:57:43 Testing Objects for Properties
1:59:15 Manipulating Complex Objects
2:01:00 Nested Objects
2:01:53 Nested Arrays
2:03:06 Record Collection
2:10:15 While Loops
2:11:35 For Loops
2:13:56 Odd Numbers With a For Loop
2:15:28 Count Backwards With a For Loop
2:17:08 Iterate Through an Array with a For Loop
2:19:43 Nesting For Loops
2:22:45 Do…While Loops
2:24:12 Profile Lookup
2:28:18 Random Fractions
2:28:54 Random Whole Numbers
2:30:21 Random Whole Numbers within a Range
2:31:46 parseInt Function
2:32:36 parseInt Function with a Radix
2:33:29 Ternary Operator
2:34:57 Multiple Ternary Operators
2:36:57 var vs let
2:39:02 var vs let scopes
2:41:32 const Keyword
2:43:40 Mutate an Array Declared with const
2:44:52 Prevent Object Mutation
2:47:17 Arrow Functions
2:28:24 Arrow Functions with Parameters
2:49:27 Higher Order Arrow Functions
2:53:04 Default Parameters
2:54:00 Rest Operator
2:55:31 Spread Operator
2:57:18 Destructuring Assignment: Objects
3:00:18 Destructuring Assignment: Nested Objects
3:01:55 Destructuring Assignment: Arrays
3:03:40 Destructuring Assignment with Rest Operator to Reassign Array
3:05:05 Destructuring Assignment to Pass an Object
3:06:39 Template Literals
3:10:43 Simple Fields
3:12:24 Declarative Functions
3:12:56 class Syntax
3:15:11 getters and setters
3:20:25 import vs require
3:22:33 export
3:23:40 * to Import
3:24:50 export default
3:25:26 Import a Default Export
📺 The video in this post was made by freeCodeCamp.org
The origin of the article: https://www.youtube.com/watch?v=PkZNo7MFNFg&list=PLWKjhJtqVAblfum5WiQblKPwIbqYXkDoC&index=4

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#javascript #learn javascript #learn javascript for beginners #learn javascript - full course for beginners #javascript programming language

Learning JavaScript: Working with Strings

Strings are the second most common data type used in JavaScript, and in many cases, since JavaScript is so widely used for web applications, it is the prominent data type. In this article I’ll discuss how strings work in JavaScript and how to work with them efficiently and effectively. I’ll also discuss some newer abilities of strings that are just being discovered and used.

Strings Defined

A string is any set of 0 or more characters enclosed in either single quotes or double quotes. The characters in a string can be alphabetic characters, numbers, symbols, and spaces. Here are some examples of JavaScript string literals:

"hello world"
'good bye, world!'
"1600 Pennsylvania Avenue"
'$*&!@ it!'

If you are using single quotes in your string, and you need to embed a single quote to write out a contraction, you use the backslash character (\) as an escape character. To see why you need to do this, let’s look at what happens when you don’t escape a single quote by writing out such a string in the JavaScript shell:

js> 'can't'
typein:1:5 SyntaxError: unexpected token: identifier:
typein:1:5 'can't'
typein:1:5 .....^

The interpreter can’t figure out what to do with the ‘t’ after the single quote.

Now watch what happens when we escape the single quote:

js> 'can\'t'
"can't"

The escape character tells the interpreter to treat the single quote as an apostrophe and not as an “end-of-string” character.

You can embed other characters into a string, including the newline character (\n) and the tab character (\t). Here are some examples using the shell:

js> print("Hello, \n world!");
Hello,
world!
js> print("Hello, \tworld");
Hello,  world

#javascript-training #learn-to-code #learn-to-program #javascript #javascript-tutorial #deep learning

Learning JavaScript: Computing with Object Methods

JavaScript has a set of built-in methods you can use with your user-defined objects. In this article I’m going to discuss several of these methods and how you can use them in your JavaScript programs.

Object.assign

The Object.assign method is used to make a copy of one object into another object. The syntax template for this method is:

Object.assign(target, source);

where source is the object you are copying from and target is the object you are copying into. This method returns the target object if you want to assign it.

Here is a sample program that demonstrates how to use Object.assign:

function Student(name, id, grades) {
  this.name = name;
  this.id = id;
  this.grades = grades;
}
let st1 = new Student("",0,[]);
et st2 = new Student("Jane Doe", 123, [91, 92, 93]);
Object.assign(st1, st2);
print(`${st1.name}, ${st1.id}\n[${st1.grades}]`);

The output from this program is:

Jane Doe, 123
[91, 92, 93]

A good reason to use this method is to make sure that a new object has all the properties and values of the old object. You may accidentally leave something out when writing your own method, while Object.assign will systematically make sure all properties and values are assigned to the new object.

Object.create

The Object.create method creates a new object from an existing object prototype. Here is the syntax template for this method:

const|let|var object-name = Object.create(existing-object);

Let’s look at a few examples to see how this method works in practice. The first example creates a new object from a function and then creates a second object using Object.create:

function Student(name, id, grades) {
  this.name = name;
  this.id = id;
  this.grades = grades;
}
let st1 = new Student("Bob Green", 1234, [81, 77, 92]);
print(`${st1.name}, ${st1.id}\n${st1.grades}`);
let st2 = Object.create(st1);
print(`${st2.name}, ${st2.id}\n${st2.grades}`);

The output from this program is:

Bob Green, 1234
81,77,92
Bob Green, 1234
81,77,92

Code must be written to change the properties of the newly created object.

#learn-to-code #javascript-development #learn-to-program #javascript #learning-javascript