🚀 Java Code Watch

A simple CLI tool to view and copy Java data structure code (like LinkedList, Stack, etc.) directly in your browser.

📦 Installation

Option 1: Use without installing (recommended)

npx javacodewatch

Option 2: Install locally

npm install chiwormjava

Run:

npx javacodewatch

Option 3: Install globally (optional)

npm install -g chiwormjava

Run:

javacodewatch

const http = require('http') const fs = require('fs')

const server = http.createServer();

server.on('request', (req, res) => { const rstream = fs.createReadStream('./product.json',"utf-8"); rstream.pipe(res); })

server.on("request", (req, res) => {

const rstream = fs.createReadStream("./product.json", "utf-8");

rstream.on("data", (chunkData) => {
    res.write(chunkData);
});

rstream.on("end", () => {
    res.end();   // ✅ correct: just end response
});

rstream.on("error", (err) => {
    console.log(err);
    res.writeHead(500, { "Content-Type": "text/plain" });
    res.end("File not found");
});

});

server.listen(3000, "127.0.0.1", () => { console.log("Server is running at http://127.0.0.1:3000"); });

import readline from "readline";

const r1 = readline.createInterface({ input: process.stdin, output: process.stdout })

// Armstrong let n; r1.question('Enter a num : ', (num) => { n = parseInt(num) let arm = 0; let og = n;

let len = num.length;

while(n > 0){
    let dig = n % 10;
    arm += Math.pow(dig,len);
    n = Math.floor(n / 10);
}
if(og == arm)
    console.log('Is Armstrong!!');
else 
    console.log('Is Not a Armstrong!!');

})

// calculator let n1, n2; r1.question('Enter the num : ', (num1) => { n1 = parseInt(num1); r1.question('Enter the num : ', (num2) => { n2 = parseInt(num2);

    let sum = n1 + n2;
    let sub = n1 - n2;
    let mul = n1 * n2;
    let div = n1 / n2;

    console.log('Addition : ', sum);
    console.log('Subtraction : ', sub);
    console.log('Multiplication : ', mul);
    console.log('Division : ', div);
})

})

// Even or ODD r1.question('Enter a num : ', (num) => { let n = num; if(n % 2 == 0) console.log('Even'); else console.log('Odd'); })

// palindrom r1.question('Enter a num : ', (num) => { let s = num.toString(); let revNum = s.split('').reverse().join(''); if(revNum == s) console.log('Is palindrome') else console.log('Not a palindrome') })

//Factorial of a Number r1.question('Enter a number: ', (num) => { let n = parseInt(num); let fact = 1;

for(let i = 1; i <= n; i++){
    fact *= i;
}

console.log('Factorial:', fact);

});

//Fibonacci Series r1.question('Enter number of terms: ', (num) => { let n = parseInt(num); let a = 0, b = 1;

console.log(a);
console.log(b);

for(let i = 2; i < n; i++){
    let next = a + b;
    console.log(next);
    a = b;
    b = next;
}

});

//Prime Number Check r1.question('Enter a number: ', (num) => { let n = parseInt(num); let isPrime = true;

if(n <= 1) isPrime = false;

for(let i = 2; i <= Math.sqrt(n); i++){
    if(n % i === 0){
        isPrime = false;
        break;
    }
}

console.log(isPrime ? 'Prime' : 'Not Prime');

});

//Sum of Digits r1.question('Enter a number: ', (num) => { let n = parseInt(num); let sum = 0;

while(n > 0){
    sum += n % 10;
    n = Math.floor(n / 10);
}

console.log('Sum of digits:', sum);

});

//Reverse a Number r1.question('Enter a number: ', (num) => { let n = parseInt(num); let rev = 0;

while(n > 0){
    let digit = n % 10;
    rev = rev * 10 + digit;
    n = Math.floor(n / 10);
}

console.log('Reversed number:', rev);

});

//Largest of Three Numbers r1.question('Enter first number: ', (a) => { r1.question('Enter second number: ', (b) => { r1.question('Enter third number: ', (c) => {

        let n1 = parseInt(a);
        let n2 = parseInt(b);
        let n3 = parseInt(c);

        let max = Math.max(n1, n2, n3);

        console.log('Largest:', max);
    });
});

});

//Largest of Three Numbers r1.question('Enter a number: ', (num) => { let n = parseInt(num);

for(let i = 1; i <= 10; i++){
    console.log(`${n} x ${i} = ${n * i}`);
}

});

//Count Digits r1.question('Enter a number: ', (num) => { let count = num.length; console.log('Total digits:', count); });

const http = require("http"); const fs = require("fs"); const path = require("path");

let counter = 0;

// Read HTML template const content = fs.readFileSync("./indexFinal.html", "utf-8");

const server = http.createServer((req, res) => {

counter++;
console.log(`Server hit ${counter} times`);

let url = req.url.toLowerCase();

// Serve CSS
if (url === "/style.css") {
    const cssPath = path.join(__dirname, "style.css");
    const style = fs.readFileSync(cssPath, "utf-8");

    res.writeHead(200, { "Content-Type": "text/css" });
    return res.end(style);
}

// Routing pages
let pageContent = "";

if (url === "/" || url === "/home") {
    pageContent = "🏠 Welcome to Home Page";
} 
else if (url === "/about") {
    pageContent = "📖 About Us Page";
} 
else if (url === "/contact") {
    pageContent = "📞 Contact Page";
} 
else if (url === "/support") {
    pageContent = "🛠 Support Page";
} 
else {
    res.writeHead(404, { "Content-Type": "text/html" });
    return res.end(content.replace("{{CONTENT}}", " 404 Page Not Found"));
}

// Common response
res.writeHead(200, { "Content-Type": "text/html" });
res.end(content.replace("{{CONTENT}}", pageContent));

});

server.listen(3000, "127.0.0.1", () => { console.log("Server running at http://127.0.0.1:3000"); });

const http = require("http"); const fs = require("fs");

let counter = 0;

const content = fs.readFileSync("./Template/index.html", "utf-8");

const server = http.createServer((request, response) => {

counter++;
console.log(`Server started ${counter} times`);

let path = request.url.toLowerCase();


if (path === "/" || path === "/home") {
    response.writeHead(200, { "Content-Type": "text/html" });
    response.end(content.replace("{{CONTENT}}", "You are in home page"));
}


else if (path === "/about") {
    response.writeHead(200, { "Content-Type": "text/html" });
    response.end(content.replace("{{CONTENT}}", "You are in about us page"));
}


else if (path === "/contact") {
    response.writeHead(200, { "Content-Type": "text/html" });
    response.end(content.replace("{{CONTENT}}", "You are in contact page"));
}


else if (path === "/support") {
    response.writeHead(200, { "Content-Type": "text/html" });
    response.end(content.replace("{{CONTENT}}", "Support me aagya bhai"));
}


else if (path === "/product") {

    fs.readFile("./data/products.json", "utf-8", (error, jsonData) => {

        if (error) {
            response.writeHead(500, { "Content-Type": "text/plain" });
            return response.end("Error reading JSON file");
        }

        response.writeHead(200, { "Content-Type": "application/json" });
        response.end(jsonData);
    });
}

// 404
else {
    response.writeHead(404, { "Content-Type": "text/html" });
    response.end(content.replace("{{CONTENT}}", "Error : 404 NOT FOUND"));
}

});

server.listen(3000, "127.0.0.1", () => { console.log("Server running at http://127.0.0.1:3000"); });

[ { "id": 1, "name": "Laptop", "price": 60000 }, { "id": 2, "name": "Phone", "price": 20000 }, { "id": 3, "name": "Tablet", "price": 30000 } ]

GET

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

const app = express();

// Helper function to read data function getProducts() { const data = fs.readFileSync('./product.json', 'utf-8'); return JSON.parse(data).products; }

// Home route app.get('/', (req, res) => { res.status(200).send('You are on home page'); });

// About route app.get('/about', (req, res) => { res.status(200).send('You are on about page'); });

// Get all products app.get('/product', (req, res) => { const products = getProducts();

res.status(200).json({
    status: 'success',
    results: products.length,
    data: products
});

});

// Get single product by ID app.get('/product/:id', (req, res) => { const products = getProducts(); const id = parseInt(req.params.id);

const product = products.find(el => el.id === id);

if (!product) {
    return res.status(404).json({
        status: 'fail',
        message: 'Product not found'
    });
}

res.status(200).json({
    status: 'success',
    data: product
});

});

// Contact route app.get('/contact', (req, res) => { res.status(200).send('You are on contact page'); });

app.listen(3000, () => { console.log('Server running on port 3000'); });

POST

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

const app = express();

app.use(express.json());

function getProducts() { const data = fs.readFileSync('./product.json', 'utf-8'); return JSON.parse(data).products; }

function saveProducts(products) { fs.writeFileSync('./product.json', JSON.stringify({ products }, null, 2)); }

app.post('/product', (req, res) => {

const products = getProducts();
const newProduct = req.body;


if (!newProduct.name || !newProduct.price) {
    return res.status(400).json({
        status: 'fail',
        message: 'Name and price are required'
    });
}


const newId = products.length > 0 
    ? products[products.length - 1].id + 1 
    : 1;

newProduct.id = newId;

products.push(newProduct);

saveProducts(products);

res.status(201).json({
    status: 'success',
    message: 'Product added successfully',
    data: newProduct
});

});

app.listen(3000, () => { console.log('Server running on port 3000'); });

PATCH

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

const app = express();

app.use(express.json());

// Helper functions function getProducts() { const data = fs.readFileSync('./product.json', 'utf-8'); return JSON.parse(data).products; }

function saveProducts(products) { fs.writeFileSync('./product.json', JSON.stringify({ products }, null, 2)); }

app.patch('/product/:id', (req, res) => {

const products = getProducts();
const id = parseInt(req.params.id);

const product = products.find(el => el.id === id);


if (!product) {
    return res.status(404).json({
        status: 'fail',
        message: 'Product not found'
    });
}


if (req.body.id) {
    return res.status(400).json({
        status: 'fail',
        message: 'Cannot update product id'
    });
}


Object.assign(product, req.body);

saveProducts(products);

res.status(200).json({
    status: 'success',
    message: 'Product updated successfully',
    data: product
});

});

app.listen(3000, () => { console.log('Server running on port 3000'); });

DELETE

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

const app = express();

app.use(express.json());

function getProducts() { const data = fs.readFileSync('./product.json', 'utf-8'); return JSON.parse(data).products; }

function saveProducts(products) { fs.writeFileSync('./product.json', JSON.stringify({ products }, null, 2)); }

app.delete('/product/:id', (req, res) => {

const products = getProducts();
const id = parseInt(req.params.id);


const index = products.findIndex(el => el.id === id);


if (index === -1) {
    return res.status(404).json({
        status: 'fail',
        message: 'Product not found'
    });
}


const deletedProduct = products.splice(index, 1);

saveProducts(products);

res.status(200).json({
    status: 'success',
    message: 'Product deleted successfully',
    data: deletedProduct[0]
});

});

app.listen(3000, () => { console.log('Server running on port 3000'); });

PUT

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

const app = express();

app.use(express.json());

// Helper functions function getProducts() { const data = fs.readFileSync('./product.json', 'utf-8'); return JSON.parse(data).products; }

function saveProducts(products) { fs.writeFileSync('./product.json', JSON.stringify({ products }, null, 2)); }

// PUT: Replace product completely app.put('/product/:id', (req, res) => {

const products = getProducts();
const id = parseInt(req.params.id);

const index = products.findIndex(el => el.id === id);


if (index === -1) {
    return res.status(404).json({
        status: 'fail',
        message: 'Product not found'
    });
}

const newData = req.body;


if (!newData.name || !newData.price) {
    return res.status(400).json({
        status: 'fail',
        message: 'Name and price are required'
    });
}


newData.id = id;


products[index] = newData;

saveProducts(products);

res.status(200).json({
    status: 'success',
    message: 'Product replaced successfully',
    data: newData
});

});

app.listen(3000, () => { console.log('Server running on port 3000'); });

chalk

const chalk = require('chalk');

console.log(chalk.red.bold('Error!')); console.log(chalk.green.underline('Success!')); console.log(chalk.blue.italic('Info message')); console.log(chalk.white.bgBlue.bold(' Important Message ')); console.log(chalk.black.bgYellow(' Warning Block ')); console.log(chalk.bgRed.white.bold(' Critical Error ')); console.log(chalk.rgb(255, 136, 0)('Custom Orange Text')); console.log(chalk.hex('#00FFAA')('Hex Color Text')); console.log(chalk.bgHex('#FF5733').white('Styled Background')); console.log( chalk.blue('Hello ' + chalk.yellow.bold('World') + '!') ); console.log( chalk.red('H') + chalk.yellow('e') + chalk.green('l') + chalk.blue('l') + chalk.magenta('o') );