All posts by : asad

Building a Simple Counter App with ReactJS

In this exercise, you will build a simple counter app using ReactJS. The app will have a button that, when clicked, increments a counter. Here’s what you need to do:

1. Set up a new ReactJS project

You can use the Create React App tool to quickly set up a new ReactJS project. Simply run the following command in your terminal:

lua

npx create-react-app my-counter-app

2. Create a new component

In your newly created ReactJS project, create a new component called “Counter”. This component will be responsible for rendering the counter and the button. To do this, create a new file called “Counter.js” in the “src” directory.

3. Write the component’s state

The state of the component will contain the counter value. To define the state, you can use the useState hook. Add the following code to the “Counter.js” file:

javascript

import React, { useState } from 'react';

const Counter = () => {
  const [count, setCount] = useState(0);

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
};

export default Counter;

This code defines a simple component that contains a paragraph element displaying the counter value and a button that, when clicked, increments the counter value by calling the setCount function.

4. Render the component

Next, you need to render the “Counter” component in your ReactJS app. To do this, open the “src/App.js” file and replace the contents with the following code:

javascript

import React from 'react';
import Counter from './Counter';

function App() {
  return (
    <div className="App">
      <Counter />
    </div>
  );
}

export default App;

5. Start the app

Now that you have written the code for your counter app, you can start the app by running the following command in your terminal:

sql

npm start

This will start the app in your browser and you should see the counter value displayed on the screen along with the “Increment” button.

6. Test the app

Finally, test the app by clicking the “Increment” button. You should see the counter value increment each time you click the button.

Congratulations! You have successfully built a simple counter app using ReactJS.

ReactJS is a popular JavaScript library for building user interfaces. In this tutorial, we will create a simple ReactJS app that displays a list of tasks.

Step 1: Set up a ReactJS project

To get started with ReactJS, you’ll need to have Node.js and npm installed on your machine. Once you have those, you can create a new ReactJS project using a tool like Create React App. To do this, run the following command in your terminal:

lua

npx create-react-app my-app

This will create a new ReactJS project in a directory called “my-app”.

Step 2: Create a Task Component

In ReactJS, components are the building blocks of your app. We will create a Task component that will display a single task. To do this, create a new file called “Task.js” in the “src” directory and add the following code:

javascript

import React from 'react';

function Task({ task }) {
  return <div>{task.text}</div>;
}

export default Task;

This code defines a simple Task component that takes a task as a prop and returns a div containing the task text.

Step 3: Create a Task List Component

Next, we will create a TaskList component that will display a list of tasks. To do this, create a new file called “TaskList.js” in the “src” directory and add the following code:

javascript

import React from 'react';
import Task from './Task';

function TaskList({ tasks }) {
  return (
    <div>
      {tasks.map((task) => (
        <Task key={task.id} task={task} />
      ))}
    </div>
  );
}

export default TaskList;

This code defines a TaskList component that takes an array of tasks as a prop and returns a div containing a Task component for each task.

Step 4: Update the App Component

Finally, we will update the App component to display our TaskList. Open the “App.js” file in the “src” directory and replace the code with the following:

javascript

import React from 'react';
import TaskList from './TaskList';

function App() {
  const tasks = [
    { id: 1, text: 'Task 1' },
    { id: 2, text: 'Task 2' },
    { id: 3, text: 'Task 3' },
  ];

  return (
    <div className="App">
      <TaskList tasks={tasks} />
    </div>
  );
}

export default App;

This code defines an App component that returns a TaskList component with an array of tasks as a prop.

Step 5: Start the app

Now that we have created our components, we can start the app. To do this, run the following command in your terminal:

sql

npm start

This will start a development server and you should be able to see the list of tasks displayed in your browser.

NestJS is a modern and progressive framework for building server-side applications. It is built on top of TypeScript and provides a robust platform for developing scalable and efficient applications. In this tutorial, we will walk through the process of building a simple REST API using NestJS.

Step 1: Install NestJS and create a new project

To get started with NestJS, you’ll need to have Node.js and npm installed on your machine. Once you have those, you can install the Nest CLI by running the following command in your terminal:

css

npm i -g @nestjs/cli

Once the Nest CLI is installed, you can create a new project by running the following command:

javascript

nest new my-api

This will create a new NestJS project in a directory called “my-api”.

Step 2: Define a simple REST endpoint

In this tutorial, we will create a simple REST endpoint that returns a list of books. To do this, we will first create a controller. To do this, run the following command in your terminal:

nest generate controller books

This will create a new controller in the “books” directory. We can now define our REST endpoint in this controller. Open the “books.controller.ts” file and add the following code:

kotlin

import { Controller, Get } from '@nestjs/common';

@Controller('books')
export class BooksController {
  @Get()
  findAll() {
    return [{ title: 'The Great Gatsby' }, { title: 'To Kill a Mockingbird' }];
  }
}

This code defines a simple REST endpoint that returns a list of books when a GET request is sent to the “/books” endpoint.

Step 3: Start the server and test the endpoint

Now that we have defined our REST endpoint, we can start the server and test it. To do this, run the following command in your terminal:

sql

npm run start

This will start the server and you should be able to access the endpoint by sending a GET request to “http://localhost:3000/books“. To do this, you can use a tool like Postman or curl. You should see the list of books returned in the response.

Step 4: Conclusion

In this tutorial, we have shown how to get started with NestJS and build a simple REST API. NestJS provides a robust platform for building server-side applications and offers many benefits over traditional server-side frameworks. We hope this tutorial has provided a good starting point for you to start building your own applications with NestJS.