Nodejs basics sukhrob

src/cli/args.js

@@ -1,5 +1,16 @@
 const parseArgs = () => {
-    // Write your code here 
+  const args = process.argv.slice(2);
+  const output = [];
+
+  for (let i = 0; i < args.length; i += 2) {
+    if (args[i].startsWith("--") && args[i + 1]) {
+      const key = args[i].slice(2);
+      const value = args[i + 1];
+      output.push(`${key} is ${value}`);
+    }
+  }
+
+  console.log(output.join(", "));
 };
 
-parseArgs();
+parseArgs();

src/cli/env.js

@@ -1,5 +1,10 @@
 const parseEnv = () => {
-    // Write your code here 
+    const rssVars = Object.keys(process.env)
+        .filter(key => key.startsWith('RSS_'))
+        .map(key => `${key}=${process.env[key]}`)
+        .join('; '); 
+
+    console.log(rssVars);
 };
 
-parseEnv();
+parseEnv();

src/cp/cp.js

@@ -1,6 +1,13 @@
+import { spawn } from 'child_process';
+
 const spawnChildProcess = async (args) => {
-    // Write your code here
+    const child = spawn('node', ['files/script.js', ...args], {
+        stdio: ['pipe', 'pipe', 'inherit'], // Setting up IPC
+    });
+
+    process.stdin.pipe(child.stdin);
+
+    child.stdout.pipe(process.stdout);
 };
 
-// Put your arguments in function call to test this functionality
-spawnChildProcess( /* [someArgument1, someArgument2, ...] */);
+spawnChildProcess(['arg1', 'arg2']);

src/fs/copy.js

@@ -1,5 +1,36 @@
+import fs from "fs/promises";
+import path from "path";
+
 const copy = async () => {
-    // Write your code here 
+  const source = path.join(process.cwd(), "files");
+  const dest = path.join(process.cwd(), "files_copy");
+
+  const sourceExist = await fs
+    .access(source)
+    .then(() => true)
+    .catch(() => false);
+  if (!sourceExist) {
+    throw new Error("FS operation failed"); // Source foolder doesnt exist
+  }
+
+  const destExist = await fs
+    .access(dest)
+    .then(() => true)
+    .catch(() => false);
+  if (destExist) {
+    throw new Error("FS operation failed"); // destination folder already exists
+  }
+
+  await fs.mkdir(dest);
+
+  const files = await fs.readdir(source);
+
+  // copy all files from source to dest.
+  for (const file of files) {
+    const srcFile = path.join(source, file);
+    const destFile = path.join(dest, file);
+    await fs.copyFile(srcFile, destFile);
+  }
 };
 
 await copy();

src/fs/create.js

@@ -1,5 +1,18 @@
+import fs from "fs/promises";
+import path from "path";
+
 const create = async () => {
-    // Write your code here 
+  const filePath = path.join(process.cwd(), "files", "fresh.txt");
+
+  const fileExists = await fs
+    .access(filePath)
+    .then(() => true)
+    .catch(() => false);
+
+  if (fileExists) {
+    throw new Error("FS operation failed");
+  }
+  await fs.writeFile(filePath, "I am fresh and young", { encoding: "utf8" });
 };
 
-await create();
+await create();

src/fs/delete.js

@@ -1,5 +1,19 @@
+import fs from "fs/promises";
+import path from "path";
+
 const remove = async () => {
-    // Write your code here 
+  const fileToRemove = path.join(process.cwd(), "files", "fileToRemove.txt");
+
+  // at first, we need to check file exist or not
+  const fileExists = await fs
+    .access(fileToRemove)
+    .then(() => true)
+    .catch(() => false);
+  if (!fileExists) {
+    throw new Error("FS operation failed");
+  }
+
+  await fs.unlink(fileToRemove);
 };
 
-await remove();
+await remove();

src/fs/files/fresh.txt

@@ -0,0 +1 @@
+I am fresh and young

src/fs/files_copy/dontLookAtMe.txt

@@ -0,0 +1 @@
+What are you looking at?!

src/fs/files_copy/fileToRead.txt

@@ -0,0 +1,7 @@
+My content
+should
+be
+printed
+into
+console
+!

src/fs/files_copy/fresh.txt

@@ -0,0 +1 @@
+I am fresh and young

src/fs/files_copy/hello.txt

@@ -0,0 +1 @@
+Hello Node.js

src/fs/files_copy/wrongFilename.txt

@@ -0,0 +1,3 @@
+# This is a file with a wrong filename
+
+Hello from **markdown**!

src/fs/list.js

@@ -1,5 +1,26 @@
+import fs from "fs/promises";
+import path from "path";
+
 const list = async () => {
-    // Write your code here 
+  const dirPath = path.join(process.cwd(), "files");
+
+  const dirExist = await fs
+    .access(dirPath)
+    .then(() => true)
+    .catch(() => false);
+
+  if (!dirExist) {
+    throw new Error("FS operation failed");
+  }
+
+  const files = await fs.readdir(dirPath);
+  // print files as an array
+  console.log(files);
+
+  // filnames from array of files
+  files.forEach((file) => {
+    console.log(file);
+  });
 };
 
-await list();
+await list();

src/fs/read.js

@@ -1,5 +1,21 @@
+import fs from "fs/promises";
+import path from "path";
+
 const read = async () => {
-    // Write your code here 
+  const dir = path.join(process.cwd(), "files", "fileToRead.txt");
+
+  // check file status, there or not
+  const fileExist = await fs
+    .access(dir)
+    .then(() => true)
+    .catch(() => false);
+  if (!fileExist) {
+    throw new Error("FS operation failed");
+  }
+
+  // read the file content in utf-8 format
+  const content = await fs.readFile(dir, "utf-8");
+  console.log(content);
 };
 
-await read();
+await read();

src/fs/rename.js

@@ -1,5 +1,32 @@
+import fs from "fs/promises";
+import path from "path";
+
 const rename = async () => {
-    // Write your code here 
+  const oldFile = path.join(process.cwd(), "files", "wrongFilename.txt");
+  const newFile = path.join(process.cwd(), "files", "properFilename.md");
+
+  // checking oold file exits or not
+  // checking new file exits already
+  const oldFileExist = await fs
+    .access(oldFile)
+    .then(() => true)
+    .catch(() => false);
+  if (!oldFileExist) {
+    throw new Error("FS operation failed(source file doesn't exist)");
+  }
+  const newFileExist = await fs
+    .access(newFile)
+    .then(() => true)
+    .catch(() => false);
+
+  if (newFileExist) {
+    throw new Error("FS operation failed(dest file already exist)");
+  }
+  if (!oldFileExist || newFileExist) {
+    throw new Error("FS operation failed");
+  }
+
+  await fs.rename(oldFile, newFile);
 };
 
-await rename();
+await rename();

src/hash/calcHash.js

@@ -1,5 +1,24 @@
+import { createReadStream } from 'fs';
+import { createHash } from 'crypto';
+import path from 'path';
+
 const calculateHash = async () => {
-    // Write your code here 
+    const filePath = path.join('files', 'fileToCalculateHashFor.txt'); 
+    const hash = createHash('sha256');
+    const fileStream = createReadStream(filePath);
+
+    fileStream.on('data', (chunk) => {
+        hash.update(chunk);
+    });
+
+    fileStream.on('end', () => {
+        const fileHash = hash.digest('hex');
+        console.log(`SHA256 Hash: ${fileHash}`);
+    });
+
+    fileStream.on('error', (err) => {
+        console.error('Error occurred:', err);
+    });
 };
 
 await calculateHash();

src/modules/cjsToEsm.cjs → src/modules/esm.mjs

@@ -1,24 +1,22 @@
-const path = require('path');
-const { release, version } = require('os');
-const { createServer: createServerHttp } = require('http');
-require('./files/c');
+import path from 'path';
+import { release, version } from 'os';
+import { createServer as createServerHttp } from 'http';
+import './files/c.js';
 
 const random = Math.random();
-
 let unknownObject;
 
 if (random > 0.5) {
-    unknownObject = require('./files/a.json');
+    unknownObject = await import('./files/a.json');
 } else {
-    unknownObject = require('./files/b.json');
+    unknownObject = await import('./files/b.json');
 }
 
 console.log(`Release ${release()}`);
 console.log(`Version ${version()}`);
 console.log(`Path segment separator is "${path.sep}"`);
-
-console.log(`Path to current file is ${__filename}`);
-console.log(`Path to current directory is ${__dirname}`);
+console.log(`Path to current file is ${import.meta.url}`);
+console.log(`Path to current directory is ${path.dirname(import.meta.url)}`);
 
 const myServer = createServerHttp((_, res) => {
     res.end('Request accepted');
@@ -33,8 +31,7 @@ myServer.listen(PORT, () => {
     console.log('To terminate it, use Ctrl+C combination');
 });
 
-module.exports = {
+export {
     unknownObject,
     myServer,
 };
-

src/streams/files/fileToWrite.txt

@@ -0,0 +1 @@
+this is written by steam api

src/streams/read.js

@@ -1,5 +1,16 @@
+import { createReadStream } from 'fs';
+import path from 'path';
+
 const read = async () => {
-    // Write your code here 
+    const filePath = path.join('files', 'fileToRead.txt'); 
+    const fileStream = createReadStream(filePath);
+    // get chunk from datafile and write it
+    fileStream.on('data', (chunk) => {
+        process.stdout.write(chunk);
+    });
+    fileStream.on('error', (err) => {
+        console.error('Error occurred:', err);
+    });
 };
 
-await read();
+await read();

src/streams/transform.js

@@ -1,5 +1,18 @@
+import { Transform } from 'stream';
+
 const transform = async () => {
-    // Write your code here 
+    const reverseStream = new Transform({
+        transform(chunk, encoding, callback) {
+            // Reverse the chunk of text
+            callback(null, chunk.toString().split('').reverse().join(''));
+        }
+    });
+
+    process.stdin.pipe(reverseStream).pipe(process.stdout);
 };
 
-await transform();
+await transform();
+
+// THIS IS A COUSE FROM RS APP
+
+// PPA SR MORF ESUOC A SI SIHT

src/streams/write.js

@@ -1,5 +1,19 @@
+import { createWriteStream } from 'fs';
+import path from 'path';
+
 const write = async () => {
-    // Write your code here 
+    const filePath = path.join('files', 'fileToWrite.txt');
+    const fileStream = createWriteStream(filePath);
+
+    process.stdin.pipe(fileStream);
+
+    // fileStream.on('error', (err) => {
+    //     console.error('Error occurred:', err);
+    // });
+
+    // fileStream.on('finish', () => {
+    //     console.log('Data has been written to fileToWrite.txt');
+    // });
 };
 
-await write();
+await write();