task 1 Node.js basics

src/cli/args.js

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

src/cli/env.js

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

src/cp/cp.js

@@ -1,6 +1,30 @@
+import { spawn } from 'child_process';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const spawnChildProcess = async (args) => {
-  // Write your code here
+  const scriptPath = path.join(__dirname, 'files', 'script.js');
+
+  const childProcess = spawn('node', [scriptPath, ...args], {
+    stdio: ['pipe', 'pipe', 'inherit']
+  });
+
+  process.stdin.pipe(childProcess.stdin);
+  childProcess.stdout.pipe(process.stdout);
+
+  childProcess.on('error', (err) => {
+    console.error('Child process error:', err);
+  });
+
+  childProcess.on('exit', (code) => {
+    if (code !== 0) {
+      console.error(`Child process exited with code ${code}`);
+    }
+  });
 };
 
 // Put your arguments in function call to test this functionality
-spawnChildProcess( /* [someArgument1, someArgument2, ...] */);
+spawnChildProcess(['arg1', 'arg2', 'arg3']);

src/fs/copy.js

@@ -1,5 +1,28 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
 const copy = async () => {
-  // Write your code here
+  const srcFilePath = path.join(__dirname, 'files');
+  const destFilePath = path.join(__dirname, 'files_copy');
+
+  try {
+    await fs.promises.stat(srcFilePath);
+    await fs.promises.stat(destFilePath);
+    throw new Error('FS operation failed');
+  } catch (err) {
+    if (err.code !== 'ENOENT') {
+      throw new Error('FS operation failed');
+    }
+  }
+
+  try {
+    await fs.promises.cp(srcFilePath, destFilePath, { recursive: true });
+  } catch (err) {
+    throw new Error('FS operation failed');
+  }
 };
 
 await copy();

src/fs/create.js

@@ -1,5 +1,18 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const create = async () => {
-  // Write your code here
+  const filePath = path.join(__dirname, 'files', 'fresh.txt');
+
+  try {
+    await fs.promises.writeFile(filePath, 'I am fresh and young', { flag: 'wx' });
+  } catch (err) {
+    throw new Error('FS operation failed');
+  }
 };
 
 await create();

src/fs/delete.js

@@ -1,5 +1,18 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const remove = async () => {
-  // Write your code here
+  const filePath = path.join(__dirname, 'files/', 'fileToRemove.txt');
+
+  try {
+    await fs.promises.unlink(filePath);
+  } catch (err) {
+    throw new Error('FS operation failed');
+  }
 };
 
 await remove();

src/fs/list.js

@@ -1,5 +1,19 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const list = async () => {
-  // Write your code here
+  const dirPath = path.join(__dirname, 'files');
+
+  try {
+    const files = await fs.promises.readdir(dirPath);
+    console.log(files);
+  } catch (err) {
+    throw new Error('FS operation failed');
+  }
 };
 
 await list();

src/fs/read.js

@@ -1,5 +1,17 @@
+import fs from 'fs/promises';
+import path from 'path';
+import { fileURLToPath } from 'url';
 const read = async () => {
-  // Write your code here
+  const __filename = fileURLToPath(import.meta.url);
+  const __dirname = path.dirname(__filename);
+  const filePath = path.join(__dirname, 'files', 'fileToRead.txt');
+
+  try {
+    const data = await fs.readFile(filePath, 'utf8');
+    console.log(data);
+  } catch (err) {
+    throw new Error('FS operation failed');
+  }
 };
 
 await read();

src/fs/rename.js

@@ -1,5 +1,34 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const rename = async () => {
-  // Write your code here
+  const oldPath = path.join(__dirname, 'files', 'wrongFilename.txt');
+  const newPath = path.join(__dirname, 'files', 'properFilename.md');
+
+  try {
+    await fs.promises.access(oldPath);
+  } catch (err) {
+    throw new Error('FS operation failed');
+  }
+
+  try {
+    await fs.promises.access(newPath);
+    throw new Error('FS operation failed');
+  } catch (err) {
+    if (err.message === 'FS operation failed') {
+      throw err;
+    }
+  }
+
+  try {
+    await fs.promises.rename(oldPath, newPath);
+  } catch (err) {
+    throw new Error('FS operation failed');
+  }
 };
 
 await rename();

src/hash/calcHash.js

@@ -1,5 +1,27 @@
+import fs from 'fs';
+import crypto from 'crypto';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const calculateHash = async () => {
-  // Write your code here
+  const filePath = path.join(__dirname, 'files', 'fileToCalculateHashFor.txt');
+  const hash = crypto.createHash('sha256');
+  const readStream = fs.createReadStream(filePath);
+
+  readStream.on('data', (chunk) => {
+    hash.update(chunk);
+  });
+
+  readStream.on('end', () => {
+    console.log(hash.digest('hex'));
+  });
+
+  readStream.on('error', (err) => {
+    throw new Error('Hash calculation failed');
+  });
 };
 
 await calculateHash();

src/modules/esm.mjs

@@ -0,0 +1,43 @@
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { release, version } from 'node:os';
+import { createServer as createServerHttp } from 'node:http';
+import { readFile } from 'node:fs/promises';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+await import('./files/c.cjs');
+
+const random = Math.random();
+
+let unknownObject;
+if (random > 0.5) {
+  const data = await readFile(new URL('./files/a.json', import.meta.url));
+  unknownObject = JSON.parse(data);
+} else {
+  const data = await readFile(new URL('./files/b.json', import.meta.url));
+  unknownObject = JSON.parse(data);
+}
+
+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}`);
+
+const myServer = createServerHttp((_, res) => {
+  res.end('Request accepted');
+});
+
+const PORT = 3000;
+
+console.log(unknownObject);
+
+myServer.listen(PORT, () => {
+  console.log(`Server is listening on port ${PORT}`);
+  console.log('To terminate it, use Ctrl+C combination');
+});
+
+export { unknownObject, myServer };

src/streams/read.js

@@ -1,5 +1,19 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const read = async () => {
-  // Write your code here
+  const filePath = path.join(__dirname, 'files', 'fileToRead.txt');
+  const readStream = fs.createReadStream(filePath, 'utf-8');
+
+  readStream.pipe(process.stdout);
+
+  readStream.on('error', (err) => {
+    throw new Error('Read operation failed');
+  });
 };
 
 await read();

src/streams/transform.js

@@ -1,5 +1,10 @@
-const transform = async () => {
-  // Write your code here
-};
+import { Transform } from 'stream';
 
-await transform();
+const reverseTransform = new Transform({
+  transform(chunk, encoding, callback) {
+    const reversed = chunk.toString().split('').reverse().join('');
+    callback(null, reversed);
+  }
+});
+
+process.stdin.pipe(reverseTransform).pipe(process.stdout);

src/streams/write.js

@@ -1,5 +1,19 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const write = async () => {
-  // Write your code here
+  const filePath = path.join(__dirname, 'files', 'fileToWrite.txt');
+  const writeStream = fs.createWriteStream(filePath);
+
+  process.stdin.pipe(writeStream);
+
+  writeStream.on('error', (err) => {
+    throw new Error('Write operation failed');
+  });
 };
 
 await write();