PHP vs Backend Node

Using Node.js as a backend developer has become increasingly popular due to its non-blocking, event-driven architecture and the ability to use JavaScript on both the client and server sides. Here's a guide on how to use Node.js as a backend developer:

1. Install Node.js:

• Before you can start working with Node.js, you need to install it on your machine. Visit the official Node.js website to download and install the latest version.

2. Create a Simple Node.js Server:

• Create a basic Node.js server using the built-in http module. Below is a simple example:
  

   const http = require('http');
  
   const server = http.createServer((req, res) => {
     res.writeHead(200, { 'Content-Type': 'text/plain' });
     res.end('Hello, World!');
   });
  
   const PORT = 3000;
   server.listen(PORT, () => {
     console.log(`Server running at http://localhost:${PORT}/`);
   });
  

3. Express.js for Web Applications:

• Express.js is a popular web application framework for Node.js. Install it using:
  

   npm install express
  

• Example of a basic Express.js server:
  

   const express = require('express');
   const app = express();
   const PORT = 3000;
  
   app.get('/', (req, res) => {
     res.send('Hello, Express!');
   });
  
   app.listen(PORT, () => {
     console.log(`Server running at http://localhost:${PORT}/`);
   });
  

4. Working with Middleware:

• Express allows you to use middleware for various purposes. Middleware can handle tasks like parsing request bodies, handling authentication, and more.

5. Connect to a Database:

• Use Node.js packages to connect to databases. Popular choices include MongoDB with Mongoose for NoSQL databases or MySQL with mysql2 for SQL databases.

6. Authentication and Authorization:

• Implement authentication and authorization using packages like Passport.js for authentication and jsonwebtoken for handling JSON Web Tokens (JWT).

7. RESTful API Development:

• Build RESTful APIs using Express.js. Define routes, handle HTTP methods (GET, POST, PUT, DELETE), and interact with the database.

8. Error Handling:

• Implement error handling for better application robustness. Express.js provides middleware for handling errors.

9. Testing:

• Use testing frameworks like Mocha and assertion libraries like Chai for writing unit tests.

10. Containerization and Deployment:

• Containerize your Node.js application using tools like Docker. Deploy your application on cloud platforms like AWS, Azure, or Heroku.

11. Logging and Monitoring:

• Implement logging using libraries like Winston. Set up monitoring and performance tracking with tools like New Relic or Prometheus.

12. Explore Frameworks and Libraries:

• Explore other Node.js frameworks and libraries based on your project needs. For example, Nest.js for building scalable and maintainable server-side applications.

13. Stay Updated:

• The Node.js ecosystem is dynamic, and new tools and practices are continually emerging. Stay updated by following blogs, forums, and official documentation.

Node.js offers a wide range of tools and libraries, making it versatile for backend development. The steps above provide a foundation for building scalable, performant, and maintainable backend applications using Node.js.

In a follow-up interview for a backend development role with a focus on Node.js, you might encounter more in-depth questions that assess your understanding of Node.js, backend development concepts, and your problem-solving skills. Here are some potential follow-up interview questions:

1. Event Loop and Asynchronous Programming:

   • Can you explain the event loop in Node.js and how it enables asynchronous programming? How does the event-driven, non-blocking architecture benefit Node.js applications?

2. Middleware in Express.js:

   • Describe how middleware works in Express.js. Provide an example of a custom middleware you've used or created in the past and explain its purpose.

3. Database Transactions:

   • How do you handle database transactions in Node.js? Discuss the importance of transactions and provide an example scenario where transactions would be necessary.

4. Authentication Strategies:

   • Explain different authentication strategies you've used in Node.js applications. Discuss the advantages and disadvantages of token-based authentication compared to session-based authentication.

5. Error Handling Strategies:

   • What strategies do you use for error handling in a Node.js application? How would you handle unhandled promise rejections, and what tools or libraries can help with error tracking?

6. Scalability and Load Balancing:

   • How can you make a Node.js application scalable, especially in a production environment with high traffic? Discuss the concept of load balancing and how it is achieved in a Node.js application.

7. Security Best Practices:

   • What security best practices do you follow when developing a Node.js application? Discuss measures such as input validation, parameterized queries, and preventing common security vulnerabilities.

8. Testing Strategies:

   • Describe your approach to testing in Node.js. How do you write unit tests for asynchronous code, and what tools or frameworks do you use for testing?

9. Containerization and Deployment:

   • Explain the benefits of containerization for a Node.js application. How would you use Docker to containerize a Node.js app, and what considerations are important for deployment?

10. Performance Optimization:

    • Discuss techniques for optimizing the performance of a Node.js application. What tools or methodologies do you use to identify and address performance bottlenecks?

11. RESTful API Design:

    • How do you design a RESTful API in a Node.js application? Discuss the principles of REST, resource naming conventions, and how to handle versioning in APIs.

12. Serverless Computing:

    • What is serverless computing, and how does it relate to Node.js? Discuss the advantages and challenges of using serverless architecture for backend services.

Remember to provide clear and concise answers, draw from your real-world experiences, and be prepared to discuss specific projects or challenges you've encountered in your previous work. Demonstrating a deep understanding of Node.js and backend development concepts will showcase your expertise to the interviewer.

Certainly! Let's provide simple answers with examples for each follow-up question:

1. Event Loop and Asynchronous Programming:

   • Answer: The event loop is a key part of Node.js that manages asynchronous tasks. It allows non-blocking code execution. For example, when reading a file, you don't wait for the file to be read before moving on to the next task.

2. Middleware in Express.js:

   • Answer: Middleware in Express.js are functions that process HTTP requests. An example is logging middleware that logs information about incoming requests.

3. Database Transactions:

   • Answer: Database transactions ensure that a series of database operations are atomic. For example, transferring money between two bank accounts involves two database updates - deducting from one and adding to the other - both should succeed or fail together.

4. Authentication Strategies:

   • Answer: Token-based authentication uses tokens for user identity verification. For example, a user logs in, receives a token, and sends it with subsequent requests. This token verifies their identity.

5. Error Handling Strategies:

   • Answer: Error handling is crucial for robust applications. For example, handling unhandled promise rejections can be done using process.on('unhandledRejection', ...), and tools like Sentry can help track and analyze errors.

6. Scalability and Load Balancing:

   • Answer: Scalability ensures an application can handle increased load. Load balancing distributes requests across multiple servers. For example, using Nginx as a load balancer for multiple Node.js instances.

7. Security Best Practices:

   • Answer: Security practices include input validation to prevent malicious input. For example, validating and sanitizing user input to avoid SQL injection attacks.

8. Testing Strategies:

   • Answer: Testing is essential for bug-free applications. For example, using Mocha and Chai for unit testing, and tools like Supertest for API testing in Node.js.

9. Containerization and Deployment:

   • Answer: Containerization packages applications with dependencies. Docker is a popular tool. For example, creating a Dockerfile to package a Node.js app, then deploying it on a cloud platform like AWS.

10. Performance Optimization:

    • Answer: Optimizing performance ensures fast response times. For example, caching frequently used data, using a Content Delivery Network (CDN), and optimizing database queries.

11. RESTful API Design:

    • Answer: RESTful APIs follow principles for simplicity and scalability. For example, using clear endpoint names like /users and HTTP methods like GET, POST, PUT, DELETE to perform CRUD operations.

12. Serverless Computing:

    • Answer: Serverless architecture allows running code without managing servers. For example, using AWS Lambda to run Node.js functions without provisioning servers, paying only for actual usage.

    Certainly! Let's provide code examples for each of the follow-up questions:

1. Event Loop and Asynchronous Programming:

// Example of asynchronous code using setTimeout
console.log("Start");
setTimeout(() => {
  console.log("Inside setTimeout");
}, 1000);
console.log("End");

2. Middleware in Express.js:

const express = require('express');
const app = express();

// Middleware example
app.use((req, res, next) => {
  console.log('Logging Middleware:', req.method, req.url);
  next();
});

app.get('/', (req, res) => {
  res.send('Hello, Express!');
});

app.listen(3000, () => {
  console.log('Server running at http://localhost:3000/');
});

3. Database Transactions:

const { Sequelize, DataTypes } = require('sequelize');
const sequelize = new Sequelize('sqlite::memory:');

// Define a model
const User = sequelize.define('User', {
  balance: {
    type: DataTypes.INTEGER,
    defaultValue: 0
  }
});

// Example of a database transaction
sequelize.transaction(async (transaction) => {
  await User.update({ balance: 100 }, { where: { id: 1 }, transaction });
  await User.update({ balance: 50 }, { where: { id: 2 }, transaction });
});

4. Authentication Strategies:

const express = require('express');
const jwt = require('jsonwebtoken');
const app = express();

// Example of token-based authentication
app.post('/login', (req, res) => {
  // Authenticate user (validate credentials)
  const user = { id: 1, username: 'example' };

  // Create and send a JWT token
  const token = jwt.sign({ user }, 'secret_key');
  res.json({ token });
});

5. Error Handling Strategies:

// Example of handling unhandled promise rejections
process.on('unhandledRejection', (error) => {
  console.error('Unhandled Rejection:', error);
});

// Example of using Sentry for error tracking
const Sentry = require('@sentry/node');
Sentry.init({ dsn: 'your-sentry-dsn' });

// Sample code that may throw an error
try {
  throw new Error('Example Error');
} catch (error) {
  // Capture and send the error to Sentry
  Sentry.captureException(error);
}

6. Scalability and Load Balancing:

// Example of a simple Node.js server
const http = require('http');
const server = http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('Hello, World!');
});
server.listen(3000);

// Example of using Nginx as a load balancer
// (Configuration would be done in the Nginx configuration file)

7. Security Best Practices:

// Example of input validation to prevent SQL injection
const userInput = "'; DROP TABLE users; --";
const sanitizedInput = userInput.replace(/['";]/g, ''); // Remove potentially harmful characters
console.log(sanitizedInput);

8. Testing Strategies:

// Example using Mocha and Chai for unit testing
const assert = require('chai').assert;

function add(a, b) {
  return a + b;
}

describe('Addition', () => {
  it('should return the sum of two numbers', () => {
    assert.equal(add(2, 3), 5);
  });
});

9. Containerization and Deployment:

# Example Dockerfile for Node.js application
FROM node:14

WORKDIR /usr/src/app

COPY package*.json ./

RUN npm install

COPY . .

EXPOSE 3000

CMD ["node", "app.js"]

10. Performance Optimization:

// Example of caching frequently used data
const cache = {};

function fetchDataFromDatabase(userId) {
  // Check if data is already in the cache
  if (cache[userId]) {
    return cache[userId];
  }

  // If not in cache, fetch from the database
  const data = /* fetch data from the database */;

  // Store in cache for future use
  cache[userId] = data;

  return data;
}

11. RESTful API Design:

const express = require('express');
const app = express();

// Example of a RESTful API using Express.js
app.get('/users', (req, res) => {
  // Get a list of users
  res.json({ users: [] });
});

app.post('/users', (req, res) => {
  // Create a new user
  res.status(201).json({ message: 'User created' });
});

12. Serverless Computing:

// Example of a simple AWS Lambda function
exports.handler = async (event) => {
  const response = {
    statusCode: 200,
    body: JSON.stringify('Hello from Lambda!'),
  };
  return response;
};

Note: These examples are simplified for illustration purposes and might need adjustments based on the actual use case and dependencies.

Certainly! I'll provide the output you would expect for some of the examples:

1. Event Loop and Asynchronous Programming:

Start
End
Inside setTimeout

2. Middleware in Express.js:

Visit http://localhost:3000/ in your browser and check the console:

Server running at http://localhost:3000/
Logging Middleware: GET /

3. Database Transactions:

No direct output, but it demonstrates the concept of ensuring two database updates succeed or fail together.

4. Authentication Strategies:

POST /login
Response: { "token": "your-generated-token" }

5. Error Handling Strategies:

Unhandled Rejection: Error: Example Error

6. Scalability and Load Balancing:

No direct output, but the server is running and ready for load balancing.

7. Security Best Practices:

Input: DROP TABLE users

8. Testing Strategies:

Run Mocha tests:

$ mocha
  Addition
    ✓ should return the sum of two numbers
  1 passing (10ms)

9. Containerization and Deployment:

No direct output, but it creates a Docker image ready for deployment.

10. Performance Optimization:

No specific output, but it demonstrates the concept of caching data to improve performance.

11. RESTful API Design:

Visit http://localhost:3000/users:

{ "users": [] }

12. Serverless Computing:

No direct output, but it defines an AWS Lambda function ready for deployment.

Please note that some examples might not have immediate visual outputs and may require additional interactions or observations in a real-world scenario.

Certainly! Below are comparisons between PHP array methods and JavaScript array methods, highlighting similarities and differences:

1. Creating Arrays:

PHP:

// Creating an indexed array
$colors = array('red', 'green', 'blue');

// Creating an associative array
$person = array('name' => 'John', 'age' => 30, 'city' => 'New York');

JavaScript:

// Creating an array
let colors = ['red', 'green', 'blue'];

// Creating an object (similar to an associative array in PHP)
let person = { name: 'John', age: 30, city: 'New York' };

2. Accessing Elements:

PHP:

// Accessing elements by index
$firstColor = $colors[0];

// Accessing elements by key in an associative array
$personName = $person['name'];

JavaScript:

// Accessing elements by index
let firstColor = colors[0];

// Accessing elements by key in an object
let personName = person.name;

3. Adding Elements:

PHP:

// Adding elements to the end of an array
array_push($colors, 'yellow');

// Adding elements with keys in an associative array
$person['gender'] = 'male';

JavaScript:

// Adding elements to the end of an array
colors.push('yellow');

// Adding elements with keys in an object
person.gender = 'male';

4. Removing Elements:

PHP:

// Removing elements by value
$removedColor = array_pop($colors);

// Removing elements by key in an associative array
unset($person['age']);

JavaScript:

// Removing elements from the end of an array
let removedColor = colors.pop();

// Removing elements by key in an object
delete person.age;

5. Iterating Over Arrays:

PHP:

// Using foreach loop for both indexed and associative arrays
foreach ($colors as $color) {
  // Do something with $color
}

foreach ($person as $key => $value) {
  // Do something with $key and $value
}

JavaScript:

// Using forEach method for both arrays and objects
colors.forEach(color => {
  // Do something with color
});

Object.entries(person).forEach(([key, value]) => {
  // Do something with key and value
});

6. Array Filtering:

PHP:

// Filtering elements based on a condition
$filteredColors = array_filter($colors, function($color) {
  return strlen($color) > 3;
});

JavaScript:

// Filtering elements based on a condition
let filteredColors = colors.filter(color => color.length > 3);

7. Array Mapping:

PHP:

// Mapping elements to a new array
$uppercaseColors = array_map('strtoupper', $colors);

JavaScript:

// Mapping elements to a new array
let uppercaseColors = colors.map(color => color.toUpperCase());

8. Array Reducing:

PHP:

// Reducing elements to a single value
$total = array_reduce($numbers, function($carry, $number) {
  return $carry + $number;
}, 0);

JavaScript:

// Reducing elements to a single value
let total = numbers.reduce((acc, number) => acc + number, 0);

9. Checking Existence:

PHP:

// Checking if a key exists in an array
$keyExists = array_key_exists('age', $person);

JavaScript:

// Checking if a property exists in an object
let keyExists = 'age' in person;

10. Sorting:

PHP:

// Sorting an indexed array
sort($numbers);

JavaScript:

// Sorting an array
numbers.sort((a, b) => a - b);

These comparisons provide an overview of common array operations in both PHP and JavaScript. While there are some similarities, the syntax and specific methods may differ between the two languages. Understanding these differences can be helpful when working with arrays in PHP and JavaScript.

It seems like you want to compare string handling in PHP and JavaScript with a focus on 10 specific strings. Below is a simple comparison using 10 strings in both PHP and JavaScript, along with some common operations.

PHP Example:

<?php

$phpStrings = [
    "Hello, World!",
    "PHP is powerful.",
    "Web development with PHP.",
    "Strings in PHP.",
    "Server-side scripting.",
    "PHP and JavaScript.",
    "Hypertext Preprocessor.",
    "Dynamic web pages.",
    "Backend programming.",
    "Easy integration."
];

// Using a foreach loop to iterate through each string
foreach ($phpStrings as $string) {
    // Example: Get the length of each string
    $length = strlen($string);
    echo "PHP String: $string | Length: $length\n";
}

?>

JavaScript Example:

let jsStrings = [
    "Hello, World!",
    "JavaScript is versatile.",
    "Frontend development with JS.",
    "Strings in JavaScript.",
    "Client-side scripting.",
    "PHP and JavaScript.",
    "Object-oriented programming.",
    "Interactive web pages.",
    "Asynchronous operations.",
    "Modern web applications."
];

// Using a forEach loop to iterate through each string
jsStrings.forEach((string) => {
    // Example: Get the length of each string
    let length = string.length;
    console.log(`JavaScript String: ${string} | Length: ${length}`);
});

Comparison:

1. Syntax:

   • PHP uses $variable syntax for variables.
   • JavaScript uses let/const/var variable syntax for variables.

2. Looping:

   • PHP uses foreach for arrays.
   • JavaScript uses forEach for arrays.

3. String Length:

   • In PHP, you use strlen() to get the length of a string.
   • In JavaScript, you use the length property of a string.

4. Printing Output:

   • PHP uses echo or print to output to the browser or console.
   • JavaScript uses console.log() to log output to the console.

5. Comment Syntax:

   • PHP uses // for single-line comments and /* */ for multi-line comments.
   • JavaScript uses // for single-line comments and /* */ for multi-line comments.

These are just a few basic examples, and both PHP and JavaScript offer a wide range of string manipulation functions/methods beyond simple string length operations. The choice between them often depends on the context of your application and your specific requirements.

Certainly! PHP also provides a variety of array functions that are commonly used for manipulating arrays. Here are 10 commonly used array functions in PHP:

1. foreach:
   • Iterates over each element in an array.

   $numbers = [1, 2, 3, 4];
   foreach ($numbers as $number) {
      echo $number;
   }

1. array_map:
   • Applies a callback function to each element of an array and returns a new array with the results.

   $numbers = [1, 2, 3, 4];
   $squared = array_map(function($number) {
      return $number * $number;
   }, $numbers);

1. array_filter:
   • Filters elements of an array using a callback function and returns a new array with only the elements that satisfy the callback function.

   $numbers = [1, 2, 3, 4];
   $evenNumbers = array_filter($numbers, function($number) {
      return $number % 2 === 0;
   });

1. array_search:
   • Searches the array for a given value and returns the corresponding key if successful.

   $fruits = ['apple', 'orange', 'banana'];
   $index = array_search('orange', $fruits);

1. array_reduce:
   • Reduces an array to a single value by iteratively applying a callback function.

   $numbers = [1, 2, 3, 4];
   $sum = array_reduce($numbers, function($accumulator, $current) {
      return $accumulator + $current;
   }, 0);

1. array_slice:
   • Returns a slice of an array.

   $numbers = [1, 2, 3, 4];
   $sliced = array_slice($numbers, 1, 2); // Returns [2, 3]

1. array_splice:
   • Removes a portion of the array and returns it.

   $numbers = [1, 2, 3, 4];
   $removed = array_splice($numbers, 1, 2); // Removes 2 elements starting from index 1

1. array_merge:
   • Merges two or more arrays.

   $arr1 = [1, 2];
   $arr2 = [3, 4];
   $combined = array_merge($arr1, $arr2); // Returns [1, 2, 3, 4]

1. sort:
   • Sorts an array.

   $fruits = ['apple', 'orange', 'banana'];
   sort($fruits); // Sorts the array alphabetically

1. array_reverse:

   • Returns an array with elements in reverse order.

   $numbers = [1, 2, 3, 4];
   $reversed = array_reverse($numbers); // Returns [4, 3, 2, 1]
   

These PHP array functions serve similar purposes to their JavaScript counterparts, providing flexibility and convenience when working with arrays in PHP.

JavaScript provides a variety of array methods that you can use for manipulating arrays. Here are 10 commonly used array methods in JavaScript:

1. forEach:
   • Executes a provided function once for each array element.

   let numbers = [1, 2, 3, 4];
   numbers.forEach(function(number) {
      console.log(number);
   });

1. map:
   • Creates a new array by applying a function to each element in the existing array.

   let numbers = [1, 2, 3, 4];
   let squared = numbers.map(function(number) {
      return number * number;
   });

1. filter:
   • Creates a new array with elements that satisfy a provided condition.

   let numbers = [1, 2, 3, 4];
   let evenNumbers = numbers.filter(function(number) {
      return number % 2 === 0;
   });

1. find:
   • Returns the first element in the array that satisfies a provided condition.

   let numbers = [1, 2, 3, 4];
   let found = numbers.find(function(number) {
      return number > 2;
   });

1. reduce:
   • Applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value.

   let numbers = [1, 2, 3, 4];
   let sum = numbers.reduce(function(accumulator, current) {
      return accumulator + current;
   }, 0);

1. indexOf:
   • Returns the first index at which a given element can be found in the array, or -1 if it is not present.

   let fruits = ['apple', 'orange', 'banana'];
   let index = fruits.indexOf('orange');

1. slice:
   • Returns a shallow copy of a portion of an array.

   let numbers = [1, 2, 3, 4];
   let sliced = numbers.slice(1, 3); // Returns [2, 3]

1. splice:
   • Changes the contents of an array by removing or replacing existing elements and/or adding new elements in place.

   let numbers = [1, 2, 3, 4];
   numbers.splice(1, 2); // Removes 2 elements starting from index 1

1. concat:
   • Combines two or more arrays.

   let arr1 = [1, 2];
   let arr2 = [3, 4];
   let combined = arr1.concat(arr2); // Returns [1, 2, 3, 4]

1. sort:
   • Sorts the elements of an array in place.

   let fruits = ['apple', 'orange', 'banana'];
   fruits.sort(); // Sorts the array alphabetically

These are just a few examples, and JavaScript provides many more array methods that offer flexibility and power when working with arrays in your code.

Certainly! Here are some additional array methods in PHP and their equivalents in JavaScript:

PHP Array Functions:

1. array_keys:
   • Returns all the keys or a subset of the keys of an array.

   $assocArray = ['name' => 'John', 'age' => 25, 'city' => 'New York'];
   $keys = array_keys($assocArray);

1. array_values:
   • Returns all the values of an array.

   $assocArray = ['name' => 'John', 'age' => 25, 'city' => 'New York'];
   $values = array_values($assocArray);

1. array_flip:
   • Exchanges all keys with their associated values in an array.

   $assocArray = ['name' => 'John', 'age' => 25, 'city' => 'New York'];
   $flippedArray = array_flip($assocArray);

1. array_unique:
   • Removes duplicate values from an array.

   $numbers = [1, 2, 3, 2, 4, 1];
   $uniqueNumbers = array_unique($numbers);

1. array_push and array_pop:
   • array_push appends one or more elements to the end of an array, and array_pop removes the last element from an array.

   $stack = [1, 2, 3];
   array_push($stack, 4);
   $poppedElement = array_pop($stack);

1. array_shift and array_unshift:
   • array_shift removes the first element from an array, and array_unshift adds one or more elements to the beginning of an array.

   $queue = [1, 2, 3];
   $shiftedElement = array_shift($queue);
   array_unshift($queue, 0);

JavaScript Array Methods:

1. Object.keys:
   • Returns an array of a given object's own property names.

   let obj = { name: 'John', age: 25, city: 'New York' };
   let keys = Object.keys(obj);

1. Object.values:
   • Returns an array of a given object's own enumerable property values.

   let obj = { name: 'John', age: 25, city: 'New York' };
   let values = Object.values(obj);

1. Object.entries:
   • Returns an array of a given object's own enumerable property [key, value] pairs.

   let obj = { name: 'John', age: 25, city: 'New York' };
   let entries = Object.entries(obj);

1. Array.from:
   • Creates a new, shallow-copied array from an array-like or iterable object.

   let arrayLike = 'hello';
   let newArray = Array.from(arrayLike);

1. Array.includes:
   • Determines whether an array includes a certain element, returning true or false.

   let numbers = [1, 2, 3, 4];
   let includesThree = numbers.includes(3);

1. Array.join:
   • Joins all elements of an array into a string.

   let fruits = ['apple', 'orange', 'banana'];
   let joinedString = fruits.join(', '); // Returns "apple, orange, banana"

These additional array methods provide further functionality for working with arrays in both PHP and JavaScript, and their usage depends on specific requirements within the context of your application.

Certainly! TypeScript is a superset of JavaScript and adds static typing to the language. While the array methods themselves remain the same in TypeScript, you can use TypeScript features such as type annotations and interfaces to enhance the type safety of your code.

Here are examples of the array methods in TypeScript:

TypeScript Array Methods:

1. forEach:

   let numbers: number[] = [1, 2, 3, 4];
   numbers.forEach((number: number) => {
      console.log(number);
   });

1. map:

   let numbers: number[] = [1, 2, 3, 4];
   let squared: number[] = numbers.map((number: number) => {
      return number * number;
   });

1. filter:

   let numbers: number[] = [1, 2, 3, 4];
   let evenNumbers: number[] = numbers.filter((number: number) => {
      return number % 2 === 0;
   });

1. find:

   let numbers: number[] = [1, 2, 3, 4];
   let found: number | undefined = numbers.find((number: number) => {
      return number > 2;
   });

1. reduce:

   let numbers: number[] = [1, 2, 3, 4];
   let sum: number = numbers.reduce((accumulator: number, current: number) => {
      return accumulator + current;
   }, 0);

1. indexOf:

   let fruits: string[] = ['apple', 'orange', 'banana'];
   let index: number = fruits.indexOf('orange');

1. slice:

   let numbers: number[] = [1, 2, 3, 4];
   let sliced: number[] = numbers.slice(1, 3); // Returns [2, 3]

1. splice:

   let numbers: number[] = [1, 2, 3, 4];
   numbers.splice(1, 2); // Removes 2 elements starting from index 1

1. concat:

   let arr1: number[] = [1, 2];
   let arr2: number[] = [3, 4];
   let combined: number[] = arr1.concat(arr2); // Returns [1, 2, 3, 4]

1. sort:
   

   let fruits: string[] = ['apple', 'orange', 'banana'];
   fruits.sort(); // Sorts the array alphabetically
   

Note: TypeScript infers types in many cases, so explicit type annotations are often optional. The examples provided include type annotations for clarity. Additionally, TypeScript supports interfaces and other advanced type features that can further enhance code readability and maintainability.