Node.js basics

src/cli/args.js

@@ -1,5 +1,17 @@
 const parseArgs = () => {
-    // Write your code here 
+    const args = process.argv.slice(2);
+
+    const arrTransformArgs = args.reduce((acc, val, index, array) => {
+        if (val.startsWith("--")) {
+            const field = val.slice(2)
+            const value = array[index + 1];
+            const resultStr = `${field} is ${value}`
+            acc.push(resultStr);
+        }
+        return acc
+    }, [])
+
+    console.log(arrTransformArgs.join(", "));
 };
 
 parseArgs();

src/cli/env.js

@@ -1,5 +1,19 @@
+import { access } from 'fs/promises';
+import path from "path";
+
 const parseEnv = () => {
-    // Write your code here 
+    const envVars = process.env;
+
+    const envVarsArray = []
+
+    for (const field in envVars) {
+        if (field.startsWith('RSS_')) {
+            const envStr = `${field}=${envVars[field]}`
+            envVarsArray.push(envStr);
+        }
+    }
+
+    console.log(envVarsArray.join('; '));
 };
 
 parseEnv();

src/cp/cp.js

@@ -1,6 +1,24 @@
+import { spawn } from'child_process';
+import path from "path";
+
 const spawnChildProcess = async (args) => {
-    // Write your code here
+    const pathToScript = path.join(process.cwd(), 'src/cp/files/script.js');
+
+    const child = spawn('node', [pathToScript, ...args], {
+        stdio: ['pipe', 'pipe', 'inherit']
+    });
+
+    child.on('error', (error) => {
+        reject(`Failed to start child process: ${error.message}`);
+    });
+
+    process.stdin.pipe(child.stdin);
+    child.stdout.pipe(process.stdout);
+
+    child.on('exit', (code) => {
+        resolve(`Child process exited with code ${code}`);
+    });
 };
 
 // Put your arguments in function call to test this functionality
-spawnChildProcess( /* [someArgument1, someArgument2, ...] */);
+spawnChildProcess(['someArgument1', 'someArgument2']);

src/fs/copy.js

@@ -1,5 +1,26 @@
+import { access, cp, mkdir, readdir, copyFile } from 'fs/promises';
+import path from "path";
+
 const copy = async () => {
-    // Write your code here 
+    const sourceDir = path.join(process.cwd(), 'src/fs/files');
+    const destDir = path.join(process.cwd(), 'src/fs/files_copy');
+
+    try {
+        await access(sourceDir);
+    } catch (error) {
+        throw new Error('FS operation failed');
+    }
+
+    try {
+        await access(destDir);
+        throw new Error('FS operation failed');
+    } catch (error) {
+        if (error.code !== 'ENOENT') {
+            throw error;
+        }
+    }
+
+    cp(sourceDir, destDir, {recursive: true});
 };
 
 await copy();

src/fs/create.js

@@ -1,5 +1,19 @@
+import { access, writeFile } from 'fs/promises';
+import path from "path";
+
 const create = async () => {
-    // Write your code here 
+    const filePath = path.join(process.cwd(), 'src/fs/files', 'fresh.txt');
+
+    try {
+        await access(filePath);
+        throw new Error('FS operation failed');
+    } catch (error) {
+        if (error.code !== 'ENOENT') {
+            throw error;
+        }
+    }
+
+    await writeFile(filePath, 'I am fresh and young', 'utf8');
 };
 
 await create();

src/fs/delete.js

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

src/fs/files/fileToRead.txt

@@ -1,7 +1,3 @@
-My content
-should
-be
-printed
-into
-console
-!
+aaaa ffff ggg
+k
+oleee

src/fs/files/fileToWrite.txt

@@ -0,0 +1,5 @@
+yyyyyyyyy
+
+
+close
+

src/fs/list.js

@@ -1,5 +1,20 @@
+import { access, readdir } from 'fs/promises';
+import path from "path";
+
 const list = async () => {
-    // Write your code here 
+    const folderPath = path.join(process.cwd(), 'src/fs/files');
+
+    try {
+        await access(folderPath);
+    } catch (error) {
+        throw new Error('FS operation failed');
+    }
+
+    const files = await readdir(folderPath);
+
+    files.forEach((file) => {
+        console.log(file);
+    })
 };
 
 await list();

src/fs/read.js

@@ -1,5 +1,17 @@
+import { access, readFile } from 'fs/promises';
+import path from "path";
+
 const read = async () => {
-    // Write your code here 
+    const filePath = path.join(process.cwd(), 'src/fs/files/fileToRead.txt');
+
+    try {
+        await access(filePath)
+    } catch (error) {
+        throw new Error('FS operation failed');
+    }
+
+    const content = await readFile(filePath, 'utf8');
+    console.log(content);
 };
 
 await read();

src/fs/rename.js

@@ -1,5 +1,26 @@
+import { access, rename as renameFile } from 'fs/promises';
+import path from "path";
+
 const rename = async () => {
-    // Write your code here 
+    const oldFile = path.join(process.cwd(), 'src/fs/files/wrongFilename.txt');
+    const newFile = path.join(process.cwd(), 'src/fs/files/properFilename.md');
+
+    try {
+        await access(oldFile)
+    } catch (error) {
+        throw Error('FS operation failed');
+    }
+
+    try {
+        await access(newFile)
+        throw Error('FS operation failed');
+    } catch (error) {
+        if (error.code !== 'ENOENT') {
+            throw error;
+        }
+    }
+
+    renameFile(oldFile, newFile);
 };
 
 await rename();

src/hash/calcHash.js

@@ -1,5 +1,22 @@
+import { createReadStream  } from 'fs';
+import path from "path";
+import { createHash } from 'crypto';
+import { pipeline } from 'stream';
+import { promisify } from 'util';
+
+const pipelineAsync = promisify(pipeline);
+
 const calculateHash = async () => {
-    // Write your code here 
+    const filePath = path.join(process.cwd(), 'src/hash/files/fileToCalculateHashFor.txt');
+    const stream = createReadStream(filePath);
+    const hash = createHash('sha256');
+
+    pipeline(stream, hash, (error) => {
+        if (!error) {
+            const hexHash = hash.digest('hex');
+            console.log(hexHash);
+        }
+    });
 };
 
-await calculateHash();
+await calculateHash();

src/modules/esm.mjs

@@ -0,0 +1,43 @@
+import path from "path";
+import { readFile } from 'fs/promises';
+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) {
+    const data = await readFile(new URL('./files/a.json', import.meta.url), 'utf-8');
+    unknownObject = JSON.parse(data);
+} else {
+    const data = await readFile(new URL('./files/b.json', import.meta.url), 'utf-8');
+    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 ${import.meta.url}`);
+console.log(`Path to current directory is ${process.cwd()}`);
+
+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 +1,18 @@
+import { createReadStream  } from 'fs';
+import path from "path";
+import { pipeline } from 'stream';
+
 const read = async () => {
-    // Write your code here 
+    const filePath = path.join(process.cwd(), 'src/fs/files/fileToRead.txt');
+
+    const stream = createReadStream(filePath);
+
+    pipeline(stream, process.stdout, (error) => {
+            if (error) {
+                console.error(error.message);
+            }
+        }
+    )
 };
 
 await read();