Node.js Basics

src/cli/args.js

@@ -1,5 +1,10 @@
 const parseArgs = () => {
-  // Write your code here
+  const args = process.argv.slice(2, process.argv.length);
+
+  args.forEach((arg, index) => {
+    if (arg.startsWith("--"))
+      console.log(`${args[index]} is ${args[index + 1]}`);
+  });
 };
 
 parseArgs();

src/cli/env.js

@@ -1,5 +1,7 @@
 const parseEnv = () => {
-  // Write your code here
+  for (const key in process.env) {
+    if (key.startsWith("RSS_")) console.log(`${key}=${process.env[key]}`);
+  }
 };
 
 parseEnv();

src/cp/cp.js

@@ -1,6 +1,21 @@
+import { spawn } from "node: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 child = spawn(
+    "node",
+    [path.join(__dirname, "files/script.js"), ...args],
+    {
+      stdio: ["pipe", "pipe", "inherit"],
+    }
+  );
+
+  process.stdin.pipe(child.stdin);
+  child.stdout.pipe(process.stdout);
 };
 
 // Put your arguments in function call to test this functionality
-spawnChildProcess( /* [someArgument1, someArgument2, ...] */);
+await spawnChildProcess(["arg1", "arg2"]);

src/fs/copy.js

@@ -1,5 +1,22 @@
+import fs from "fs/promises";
+import path from "path";
+import { cp } from "fs/promises";
+import { fileURLToPath } from "url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const copy = async () => {
-  // Write your code here
+  try {
+    await fs.mkdir(path.join(__dirname, "files_copy"));
+    await cp(
+      path.resolve(__dirname, "files"),
+      path.resolve(__dirname, "files_copy"),
+      { recursive: true }
+    );
+  } catch {
+    throw new Error("fs operation failed");
+  }
 };
 
 await copy();

src/fs/create.js

@@ -1,5 +1,20 @@
+import fs from "fs/promises";
+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
+  try {
+    await fs.writeFile(
+      path.resolve(__dirname, "files/fresh.txt"),
+      "I am fresh and young",
+      { flag: "wx" }
+    );
+  } catch {
+    throw new Error("FS operation failed");
+  }
 };
 
 await create();

src/fs/delete.js

@@ -1,5 +1,16 @@
+import fs from "fs/promises";
+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
+  try {
+    await fs.unlink(path.resolve(__dirname, "files/fileToRemove.txt"));
+  } catch {
+    throw new Error("FS operation failed");
+  }
 };
 
 await remove();

src/fs/files/fileToRemove.txt

@@ -1 +0,0 @@
-How dare you!

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/fileToRemove.txt

@@ -0,0 +1 @@
+How dare you are!!!

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 +1,17 @@
+import path from "path";
+import { fileURLToPath } from "url";
+import fs from "fs/promises";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const list = async () => {
-  // Write your code here
+  try {
+    const files = await fs.readdir(path.resolve(__dirname, "files"));
+    console.log(files);
+  } catch {
+    throw new Error("FS operation failed");
+  }
 };
 
 await list();

src/fs/read.js

@@ -1,5 +1,20 @@
+import path from "path";
+import { fileURLToPath } from "url";
+import fs from "fs/promises";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const read = async () => {
-  // Write your code here
+  try {
+    const fileContent = await fs.readFile(
+      path.resolve(__dirname, "files/fileToRead.txt"),
+      { encoding: "utf-8" }
+    );
+    console.log(fileContent);
+  } catch {
+    throw new Error("FS operation failed");
+  }
 };
 
 await read();

src/fs/rename.js

@@ -1,5 +1,32 @@
+import { access } from "fs/promises";
+import { constants } from "fs/promises";
+import fs from "fs/promises";
+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
+  try {
+    const isTargetExist = await access(
+      path.resolve(__dirname, "files/properFilename.md"),
+      constants.F_OK
+    )
+      .then(() => true)
+      .catch(() => false);
+
+    if (isTargetExist) {
+      throw new Error();
+    }
+
+    await fs.rename(
+      path.resolve(__dirname, "files/wrongFilename.txt"),
+      path.resolve(__dirname, "files/properFilename.md")
+    );
+  } catch {
+    throw new Error("FS operation failed");
+  }
 };
 
 await rename();

src/hash/calcHash.js

@@ -1,5 +1,24 @@
+import crypto from "node:crypto";
+
+import path from "path";
+import { cp } from "fs/promises";
+import { fileURLToPath } from "url";
+import { createReadStream } from "node:fs";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const calculateHash = async () => {
-  // Write your code here
+  const hash = crypto.createHash("sha256");
+  const stream = createReadStream(
+    path.join(__dirname, "files/fileToCalculateHashFor.txt")
+  );
+
+  stream.on("data", (chunk) => {
+    hash.update(chunk);
+  });
+
+  stream.on("end", () => console.log(hash.digest("hex")));
 };
 
 await calculateHash();

src/modules/esm.mjs

@@ -0,0 +1,43 @@
+import path from "node:path";
+import { release, version } from "node:os";
+import { createServer as createServerHttp } from "node:http";
+import { fileURLToPath } from "url";
+import { createRequire } from "node:module";
+
+import a from "./files/a.json" with { type: "json" };
+import b from "./files/b.json" with { type: "json" };
+
+const require = createRequire(import.meta.url);
+require("./files/c.js");
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const random = Math.random();
+
+const unknownObject = random > 0.5 ? a : b
+
+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 default {
+  unknownObject,
+  myServer,
+};

src/streams/files/fileToRead.txt

@@ -1 +1 @@
-This file should be read using Streams API
+вфывфывфы

src/streams/files/fileToWrite.txt

@@ -0,0 +1,3 @@
+dfgdfg
+fdgdfg
+dfgdf

src/streams/read.js

@@ -1,5 +1,20 @@
+import { createReadStream } from "node: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 readStream = createReadStream(
+    path.resolve(__dirname, "files/fileToRead.txt")
+  );
+
+  readStream.pipe(process.stdout, { end: false });
+
+  readStream.on("end", () => {
+    console.log();
+  });
 };
 
 await read();

src/streams/transform.js

@@ -1,5 +1,22 @@
+import { createReadStream, createWriteStream } from "node:fs";
+import path from "path";
+import { fileURLToPath } from "url";
+import { Transform } from "node:stream";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const transform = async () => {
-  // Write your code here
+  const reverseStream = new Transform({
+    transform(chunk, encoding, callback) {
+      const reversedString = chunk.toString().split("").reverse().join("");
+
+      this.push(reversedString);
+      callback();
+    },
+  });
+
+  process.stdin.pipe(reverseStream).pipe(process.stdout);
 };
 
 await transform();