Nodejs basics

src/cli/args.js

@@ -1,5 +1,11 @@
 const parseArgs = () => {
-  // Write your code here
+  const args = process.argv.slice(2);
+
+  for (let i = 0; i < args.length; i+= 2) {
+    const propName = args[i].slice(2);
+    const value = args[i + 1]
+    console.log(`${propName} is ${value}`)
+  }
 };
 
 parseArgs();

src/cli/env.js

@@ -1,5 +1,9 @@
 const parseEnv = () => {
-  // Write your code here
+  const variables = process.env;
+  const filterRSS = Object.keys(variables).filter((key) => key.startsWith('RSS_'));
+  const result = filterRSS.map((el) => `${el} = ${variables[el]}`);
+
+  console.log(result);
 };
 
 parseEnv();

src/fs/copy.js

@@ -1,5 +1,32 @@
+import fsPromises from 'fs/promises';
+
+const filePath = './src/fs/files';
+const filesTo = './src/fs/files_copy'
+
 const copy = async () => {
-  // Write your code here
+  try {
+    await fsPromises.access(filePath); 
+
+    try {
+      await fsPromises.access(filesTo);
+      throw new Error('FS operation failed')
+    } catch (error) {
+      if (error.code && error.code !== 'ENOENT') { 
+        throw new Error('FS operation failed')
+      }
+    }
+    const filesInsideFilesFolder = await fsPromises.readdir(filePath);
+    await fsPromises.mkdir(filesTo);
+
+    for (let file of filesInsideFilesFolder) {
+      const from = `${filePath}/${file}`;
+      const to = `${filesTo}/${file}`
+
+      await fsPromises.copyFile(from, to);
+    }
+  } catch {
+    throw new Error('FS operation failed')
+  }
 };
 
 await copy();

src/fs/create.js

@@ -1,5 +1,20 @@
+import fsPromises from 'fs/promises';
+
+const filePath = './src/fs/files/fresh.txt';
+const message = 'I am fresh and young';
+
 const create = async () => {
-  // Write your code here
+  try {
+    await fsPromises.access(filePath);
+    throw new Error('FS operation failed')
+  }
+  catch (error) {
+  if (error.code === 'ENOENT') { 
+    await fsPromises.writeFile(filePath, message);
+    } else {
+      throw error;
+    }
+  }
 };
 
 await create();

src/fs/delete.js

@@ -1,5 +1,16 @@
+
+import fsPromises from 'fs/promises';
+const pathFile = './src/fs/files/fileToRemove.txt';
+
 const remove = async () => {
-  // Write your code here
-};
+ try {
+    await fsPromises.access(pathFile);
+    await fsPromises.unlink(pathFile);
+  } catch (error) {
+    if (error.code === 'ENOENT') {
+       throw new Error('FS operation failed');
+      }
+    }
+  };
 
 await remove();

src/fs/list.js

@@ -1,5 +1,17 @@
+import fsPromises from 'fs/promises';
+const path = './src/fs/files';
+
 const list = async () => {
-  // Write your code here
+  try {
+     await fsPromises.access(path);
+
+     const filesInsideFilesFolder = await fsPromises.readdir(path);
+     console.log(filesInsideFilesFolder);
+    } catch (error) {
+       if (error.code === 'ENOENT') {
+        throw new Error('FS operation failed');
+      }
+  }
 };
 
 await list();

src/fs/read.js

@@ -1,5 +1,15 @@
+import fsPromises from 'fs/promises';
+const path = './src/fs/files/fileToRead.txt';
+
 const read = async () => {
-  // Write your code here
+  try {
+    const fileContent = await fsPromises.readFile(path, { encoding: 'utf8' });
+    console.log(fileContent);
+  } catch (error) {
+    if (error.code === 'ENOENT') {
+      throw new Error('FS operation failed');
+    }
+  }
 };
 
 await read();

src/fs/rename.js

@@ -1,5 +1,26 @@
+import fsPromises from 'fs/promises';
+const wrongFilePath = './src/fs/files/wrongFilename.txt';
+const properFilePath = './src/fs/files/properFilename.md';
+
 const rename = async () => {
-  // Write your code here
+    try {
+      await fsPromises.access(wrongFilePath);
+    }
+    catch (error) {
+    if (error.code === 'ENOENT') {
+       throw new Error('FS operation failed');
+      }
+    }
+
+    try {
+       await fsPromises.access(properFilePath);
+       throw new Error('FS operation failed');
+    } catch (error) {
+      if (error.code !== 'ENOENT') {
+        throw new Error('FS operation failed');
+      }
+    }
+    await fsPromises.rename(wrongFilePath, properFilePath);
 };
 
 await rename();

src/hash/calcHash.js

@@ -1,5 +1,19 @@
+import fs from 'fs';
+import crypto from 'crypto';
+
+const filePath = './src/hash/files/fileToCalculateHashFor.txt';
+
 const calculateHash = async () => {
-  // Write your code here
+    const hash = crypto.createHash('sha256');
+    const readStream = fs.createReadStream(filePath)
+
+    readStream.on('data', (chunk) => {
+      hash.update(chunk);
+    })
+    readStream.on('end', () => {
+      const result = hash.digest('hex');
+      console.log(result);
+    })
 };
 
 await calculateHash();

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

@@ -1,12 +1,18 @@
-const path = require('node:path');
-const { release, version } = require('node:os');
-const { createServer: createServerHttp } = require('node:http');
+import path from 'path';
+import { release, version } from 'node:os';
+import { createServer as createServerHttp }from 'node:http';
+import { fileURLToPath } from 'url';
 
-require('./files/c.cjs');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+import a from './files/a.json' with { type: "json" };
+import b from './files/b.json' with { type: "json" };
+const c = await import('./files/c.cjs');
 
 const random = Math.random();
 
-const unknownObject = random > 0.5 ? require('./files/a.json') : require('./files/b.json');
+const unknownObject = random > 0.5 ? a : b;
 
 console.log(`Release ${release()}`);
 console.log(`Version ${version()}`);
@@ -28,7 +34,4 @@ myServer.listen(PORT, () => {
   console.log('To terminate it, use Ctrl+C combination');
 });
 
-module.exports = {
-  unknownObject,
-  myServer,
-};
+export {unknownObject, myServer}

src/streams/read.js

@@ -1,5 +1,23 @@
+import fs from 'fs';
+import { once } from 'events';
+
+const filePath = './src/streams/files/fileToRead.txt';
+
 const read = async () => {
-  // Write your code here
+  try {
+    const readStream = fs.createReadStream(filePath, { encoding: 'utf-8' });
+
+    readStream.on('error', (error) => {
+    throw error;
+});
+
+    readStream.pipe(process.stdout);
+    await once(readStream, 'end');
+
+    console.log('success');
+  } catch (error) {
+    throw error;
+  }
 };
 
 await read();

src/streams/transform.js

@@ -1,5 +1,17 @@
+import { Transform } from 'stream';
+
 const transform = async () => {
-  // Write your code here
+  const streamTransform = new Transform({transform(chunk, encoding, callback) {
+  const reversedText = chunk.toString().split('').reverse().join('');
+
+  this.push(reversedText);
+  callback();
+}
+})
+console.log('Type something. Press Ctrl+D or Ctrl+C to exit.');
+
+process.stdin.pipe(streamTransform);
+streamTransform.pipe(process.stdout);
 };
 
 await transform();

src/streams/write.js

@@ -1,5 +1,19 @@
+import fs from 'fs';
+import { once } from 'events';
+
+const filePath = './src/streams/files/fileToWrite.txt';
+
 const write = async () => {
-  // Write your code here
+  try {
+  console.log('Type something. Press Ctrl+D or Ctrl+C to exit.');
+
+  const writeStream = fs.createWriteStream(filePath);
+
+  process.stdin.pipe(writeStream);
+  await once(writeStream, 'finish')
+  } catch (error) {
+    console.error(error);
+  }
 };
 
 await write();

src/zip/compress.js

@@ -1,5 +1,28 @@
+import fs from 'fs';
+import zlib from 'zlib';
+import { once } from 'events';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const fileName = fileURLToPath(import.meta.url);
+const dirName = path.dirname(fileName);
+
+const filePath = path.join(dirName, 'files', 'fileToCompress.txt');
+const archivePath =  path.join(dirName, 'files', 'archive.gz');
+
 const compress = async () => {
-  // Write your code here
+  try {
+    const readStream = fs.createReadStream(filePath);
+    const writeStream = fs.createWriteStream(archivePath);
+    const gzip = zlib.createGzip();
+
+    readStream.pipe(gzip);
+    gzip.pipe(writeStream);
+
+    await once(writeStream, 'finish');
+  } catch (error) {
+    console.error(error);
+  }
 };
 
 await compress();

src/zip/decompress.js

@@ -1,5 +1,28 @@
+import fs from 'fs';
+import zlib from 'zlib';
+import { once } from 'events';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const fileName = fileURLToPath(import.meta.url);
+const dirName = path.dirname(fileName);
+
+const filePath = path.join(dirName, 'files', 'fileToCompress.txt');
+const archivePath =  path.join(dirName, 'files', 'archive.gz');
+
 const decompress = async () => {
-  // Write your code here
+  try {
+    const readStream = fs.createReadStream(archivePath);
+    const writeStream = fs.createWriteStream(filePath);
+    const gunzip = zlib.createGunzip();
+
+    readStream.pipe(gunzip);
+    gunzip.pipe(writeStream);
+
+    await once(writeStream, 'finish');
+  } catch (error) {
+    console.error(error);
+  }
 };
 
 await decompress();