Node basics

src/cli/args.js

@@ -1,5 +1,15 @@
 const parseArgs = () => {
-  // Write your code here
+   const args = process.argv.slice(2);
+   const composedArgs = args.reduce((acc, arg, i, arr) => {
+    if(arg.startsWith('--')) {
+      acc[arg] = null
+    } else {
+      acc[arr[i-1]] = arg
+    }
+     return acc;
+   }, {})
+   const out = Object.entries(composedArgs).map(([k,v]) => `${k} is ${v}`)
+   console.log(out.join(', '))
 };
 
 parseArgs();

src/cli/env.js

@@ -1,5 +1,6 @@
 const parseEnv = () => {
-  // Write your code here
+  const rssEnv = Object.entries(process.env).filter(([k,]) => k.startsWith('RSS_')).map(([k,v]) => `${k}=${v}`).join('; ');
+  console.log(rssEnv);
 };
 
 parseEnv();

src/fs/copy.js

@@ -1,5 +1,25 @@
+import fs from 'node:fs'
+import { createFolder } from '../utils/file-helper.js'
+import { OPERATION_FAILED } from '../utils/constants.js'
+
 const copy = async () => {
-  // Write your code here
+  const folderName = 'files_copy';
+  const from = './files'
+  const to = `./${folderName}`;
+
+  try {
+    const maybeFolder = createFolder(to);
+    if(!maybeFolder) {
+       throw new Error(OPERATION_FAILED)
+    }
+
+    fs.cpSync(from, to, {recursive: true})
+  }
+  catch (err) {
+    console.log(err);
+  }
+
+
 };
 
 await copy();

src/fs/create.js

@@ -1,5 +1,22 @@
+import fs from 'fs/promises';
+import { isFileExist } from '../utils/file-helper.js'
+import { OPERATION_FAILED } from '../utils/constants.js'
+
 const create = async () => {
-  // Write your code here
+  const path = './files/fresh.txt';
+  const content = 'I am fresh and young';
+
+  try {
+
+    if(isFileExist(path)) {
+      throw new Error(OPERATION_FAILED)
+    }
+
+    await fs.writeFile(path, content);
+
+  } catch (err) {
+    console.warn(err)
+  }
 };
 
 await create();

src/fs/delete.js

@@ -1,5 +1,15 @@
+import fs from 'fs/promises';
+import { isFileExist } from '../utils/file-helper.js'
+import { OPERATION_FAILED } from '../utils/constants.js'
+
 const remove = async () => {
-  // Write your code here
+   const path = './files/fileToRemove.txt';
+
+    if(!isFileExist(path)) {
+      throw new Error(OPERATION_FAILED);
+    }
+
+    await fs.unlink(path);
 };
 
 await remove();

src/fs/list.js

@@ -1,5 +1,26 @@
+import fs from 'fs/promises';
+import { isFileExist } from '../utils/file-helper.js'
+import { OPERATION_FAILED } from '../utils/constants.js'
+
 const list = async () => {
-  // Write your code here
+   try {
+    const path = './files';
+
+    if(!isFileExist(path)) {
+      throw new Error(OPERATION_FAILED);
+    }
+
+    const files = await fs.readdir(path);
+
+    for(let file in files) {
+      console.log(file);
+    }
+
+   } catch (err) {
+     console.log(err)
+   }
+
+
 };
 
 await list();

src/fs/read.js

@@ -1,5 +1,22 @@
+import fs from 'fs/promises';
+import { isFileExist } from '../utils/file-helper.js'
+import { OPERATION_FAILED } from '../utils/constants.js'
+
 const read = async () => {
-  // Write your code here
+  try {
+    const path = './files/fileToRead.txt';
+
+    if(!isFileExist(path)) {
+      throw new Error(OPERATION_FAILED);
+    }
+
+    const content = await fs.readFile(path, 'utf-8');
+    console.log(content);
+
+
+   } catch (err) {
+     console.log(err)
+   }
 };
 
 await read();

src/fs/rename.js

@@ -1,5 +1,16 @@
+import { isFileExist } from '../utils/file-helper.js'
+import { OPERATION_FAILED } from '../utils/constants.js'
+import fs from 'node:fs';
+
 const rename = async () => {
-  // Write your code here
+  const from = './files/wrongFilename.txt';
+  const to = './files/properFilename.md';
+
+  if(!isFileExist(from) || isFileExist(to)) {
+    throw new Error(OPERATION_FAILED)
+  }
+
+  fs.renameSync(from,to)
 };
 
 await rename();

src/hash/calcHash.js

@@ -1,5 +1,11 @@
+import fs from 'node:fs';
+import crypto from 'node:crypto';
+
 const calculateHash = async () => {
-  // Write your code here
+  const input = './files/fileToCalculateHashFor.txt';
+  const hash = crypto.createHash('sha256');
+  const in$ = fs.createReadStream(input, 'utf-8');
+  in$.pipe(hash).setEncoding('hex').pipe(process.stdout);
 };
 
 await calculateHash();

src/modules/cjsToEsm.mjs

@@ -0,0 +1,40 @@
+import path from 'node:path'
+import { release, version } from 'node:os';
+import { createServer as createServerHttp } from 'node:http';
+import { fileURLToPath } from 'node:url';
+import { dirname } from 'node:path';
+
+const cjs = await import ('./files/c.cjs');
+
+const random = Math.random();
+
+const unknownObject = random > 0.5 ? await import('./files/a.json', { with: { type: 'json' } })  : await import('./files/b.json', { with: { type: 'json' } });
+
+console.log(`Release ${release()}`);
+console.log(`Version ${version()}`);
+console.log(`Path segment separator is "${path.sep}"`);
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+console.log(`Path to current file is ${path.__filename}`);
+console.log(`Path to current directory is ${path.__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 default {
+  unknownObject,
+  myServer,
+};

src/streams/read.js

@@ -1,5 +1,14 @@
+import streams from 'node:stream/promises';
+import fs from 'node:fs';
+
 const read = async () => {
-  // Write your code here
+ const file = './files/fileToRead.txt';
+ const fileStream = fs.createReadStream(file, 'utf-8');
+
+ for await (const chunk of fileStream) {
+    process.stdout.write(chunk)
+ }
+
 };
 
 await read();

src/streams/transform.js

@@ -1,5 +1,24 @@
+import { Transform } from 'node:stream';
+
+class ReverseText extends Transform {
+  constructor(options) {
+    super(options)
+  }
+
+  _transform(chunk, encoding, cb) {
+    const str =  chunk.toString().split('').reduceRight((acc, char) => {
+      return acc + char
+    }, '')
+
+    this.push(str);
+
+    cb();
+  }
+}
+
+
 const transform = async () => {
-  // Write your code here
+  process.stdin.pipe(new ReverseText()).pipe(process.stdout)
 };
 
 await transform();

src/streams/write.js

@@ -1,5 +1,12 @@
+import stream from 'node:stream';
+import fs from 'node:fs';
+
 const write = async () => {
-  // Write your code here
+   const file = './files/fileToWrite.txt';
+   const writable = fs.createWriteStream(file);
+   process.stdin.on("data", data => {
+      writable.write(data)
+   })
 };
 
 await write();

src/utils/constants.js

@@ -0,0 +1 @@
+export const OPERATION_FAILED = 'FS operation failed';

src/utils/file-helper.js

@@ -0,0 +1,13 @@
+import { existsSync, mkdirSync } from 'node:fs';
+
+export const isFileExist = (path, error) => existsSync(path);
+
+export const createFolder = (path) => {
+	if(isFileExist(path)) {
+		return false
+	}
+
+	mkdirSync(path);
+
+	return true
+}

src/zip/compress.js

@@ -1,5 +1,16 @@
+import fs from 'node:fs';
+import streams from 'node:stream/promises';
+import zlib from 'node:zlib';
+
 const compress = async () => {
-  // Write your code here
+  const fromFile = './files/fileToCompress.txt';
+  const toFile = './files/archive.gz'
+  const from = fs.createReadStream(fromFile, 'utf-8');
+  const to = fs.createWriteStream(toFile);
+  const gzip = zlib.createGzip();
+
+  await streams.pipeline(from,gzip,to)
+
 };
 
 await compress();

src/zip/decompress.js

@@ -1,5 +1,15 @@
+import fs from 'node:fs';
+import streams from 'node:stream/promises';
+import zlib from 'node:zlib';
+
 const decompress = async () => {
-  // Write your code here
+  const toFile = './files/fileToCompress.txt';
+  const fromFile = './files/archive.gz'
+  const from = fs.createReadStream(fromFile);
+  const to = fs.createWriteStream(toFile, 'utf-8');
+  const gzip = zlib.createGunzip();
+
+  await streams.pipeline(from,gzip,to)
 };
 
 await decompress();