Nodejs basics

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+	"cSpell.words": ["asar"]
+}

src/cli/args.js

@@ -1,5 +1,18 @@
+const PREFIX = '--'
+
 const parseArgs = () => {
-  // Write your code here
-};
+	const formatArgumentsArr = process.argv
+		.slice(2)
+		.reduce((acc, value, index, array) => {
+			if (value.startsWith(PREFIX)) {
+				const argument = `${value.replace(PREFIX, '')} is ${array[index + 1]}`
+				return [...acc, argument]
+			}
+			return acc
+		}, [])
+
+	const formatArgumentsStr = formatArgumentsArr.join(', ')
+	console.log(formatArgumentsStr)
+}
 
-parseArgs();
+parseArgs()

src/cli/env.js

@@ -1,5 +1,21 @@
+const PREFIX = 'RSS_'
+
 const parseEnv = () => {
-  // Write your code here
-};
+	const envVariables = Object.entries(process.env).reduce(
+		(acc, value, index, array) => {
+			const [nameVar, valueVar] = value
+
+			if (nameVar.startsWith(PREFIX)) {
+				const variable = `${nameVar}=${valueVar}`
+				return [...acc, variable]
+			}
+			return acc
+		},
+		[]
+	)
+
+	const strFormatVariables = envVariables.join(', ')
+	console.log(strFormatVariables)
+}
 
-parseEnv();
+parseEnv()

src/cp/cp.js

@@ -1,6 +1,10 @@
-const spawnChildProcess = async (args) => {
-  // Write your code here
-};
+import path from 'node:path'
+import { fork } from 'node:child_process'
 
-// Put your arguments in function call to test this functionality
-spawnChildProcess( /* [someArgument1, someArgument2, ...] */);
+const pathFileFork = path.resolve(import.meta.dirname, 'files/script.js')
+
+const spawnChildProcess = async args => {
+	fork(pathFileFork, args)
+}
+
+spawnChildProcess(['someArgument1', 'someArgument2'])

src/cp/files/script.js

@@ -1,19 +1,19 @@
-import { EOL } from 'node:os';
-import { argv, stdout, stdin, exit } from 'node:process';
+import { EOL } from 'node:os'
+import { argv, stdout, stdin, exit } from 'node:process'
 
-const args = argv.slice(2);
+const args = argv.slice(2)
 
-console.log(`Total number of arguments is ${args.length}`);
-console.log(`Arguments: ${JSON.stringify(args)}${EOL}`);
+console.log(`Total number of arguments is ${args.length}`)
+console.log(`Arguments: ${JSON.stringify(args)}${EOL}`)
 
-const echoInput = (chunk) => {
-  const chunkStringified = chunk.toString();
+const echoInput = chunk => {
+	const chunkStringified = chunk.toString()
 
-  if (chunkStringified.includes('CLOSE')) {
-    exit(0);
-  }
+	if (chunkStringified.includes('CLOSE')) {
+		exit(0)
+	}
 
-  stdout.write(`Received from master process: ${chunk.toString()}${EOL}`);
-};
+	stdout.write(`Received from master process: ${chunk.toString()}${EOL}`)
+}
 
-stdin.on('data', echoInput);
+stdin.on('data', echoInput)

src/fs/copy.js

@@ -1,5 +1,24 @@
+import { cp } from 'fs/promises'
+import path from 'path'
+import { isFileExists } from '../../utils.js'
+
+const srcFolderPath = path.resolve(import.meta.dirname, 'files')
+const destFolderPath = path.resolve(import.meta.dirname, 'files_copy')
+const isSrcFolderPathExists = await isFileExists(srcFolderPath)
+
 const copy = async () => {
-  // Write your code here
-};
+	if (!isSrcFolderPathExists) {
+		throw new Error('FS operation failed')
+	} else {
+		await cp(srcFolderPath, destFolderPath, {
+			recursive: true,
+			errorOnExist: true,
+			force: false,
+		}).catch(error => {
+			console.log(error)
+			throw new Error('FS operation failed')
+		})
+	}
+}
 
-await copy();
+await copy()

src/fs/create.js

@@ -1,5 +1,15 @@
+import { writeFile } from 'fs/promises'
+import path from 'path'
+
+const fileUrl = path.resolve(import.meta.dirname, 'files/fresh.txt')
+
 const create = async () => {
-  // Write your code here
-};
+	try {
+		await writeFile(fileUrl, 'I am fresh and young', { flag: 'wx' })
+	} catch (err) {
+		console.log(err)
+		throw new Error('FS operation failed')
+	}
+}
 
-await create();
+await create()

src/fs/delete.js

@@ -1,5 +1,15 @@
+import { rm } from 'fs/promises'
+import path from 'path'
+
+const filePath = path.resolve(import.meta.dirname, 'files/fileToRemove.txt')
+
 const remove = async () => {
-  // Write your code here
-};
+	try {
+		await rm(filePath)
+	} catch (error) {
+		console.log(error)
+		throw new Error('FS operation failed')
+	}
+}
 
-await remove();
+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/list.js

@@ -1,5 +1,16 @@
+import { readdir } from 'fs/promises'
+import path from 'path'
+
+const folderPath = path.resolve(import.meta.dirname, 'files')
+
 const list = async () => {
-  // Write your code here
-};
+	try {
+		const listFiles = await readdir(folderPath)
+		console.log(listFiles)
+	} catch (error) {
+		console.log(error)
+		throw new Error('FS operation failed')
+	}
+}
 
-await list();
+await list()

src/fs/read.js

@@ -1,5 +1,16 @@
+import { promises as fs } from 'fs'
+import path from 'path'
+
+const filePath = path.resolve(import.meta.dirname, 'files/fileToRead.txt')
+
 const read = async () => {
-  // Write your code here
-};
+	try {
+		const fileContent = await fs.readFile(filePath, 'utf-8')
+		console.log(fileContent)
+	} catch (error) {
+		console.log(error)
+		throw new Error('FS operation failed')
+	}
+}
 
-await read();
+await read()

src/fs/rename.js

@@ -1,5 +1,18 @@
+import { rename } from 'fs/promises'
+import path from 'path'
+
+import { isFileExists } from '../../utils.js'
+
+const oldFileName = path.resolve(import.meta.dirname, 'wrongFilename.txt')
+const newFileName = path.resolve(import.meta.dirname, 'properFilename.md')
+const isNewFileNameExists = await isFileExists(newFileName)
+
 const rename = async () => {
-  // Write your code here
-};
+	if (isNewFileNameExists) {
+		throw new Error('FS operation failed')
+	} else {
+		await rename(oldFileName, newFileName)
+	}
+}
 
-await rename();
+await rename()

src/hash/calcHash.js

@@ -1,5 +1,16 @@
+import { readFile } from 'fs/promises'
+import { createHash } from 'crypto'
+import path from 'path'
+
+const filePath = path.resolve(
+	import.meta.dirname,
+	'files/fileToCalculateHashFor.txt'
+)
+
 const calculateHash = async () => {
-  // Write your code here
-};
+	const textFromFile = await readFile(filePath)
+	const hash = createHash('sha256').update(textFromFile)
+	console.log(hash.digest('hex'))
+}
 
-await calculateHash();
+await calculateHash()

src/modules/esm.mjs

@@ -0,0 +1,36 @@
+import path from 'path'
+import { release, version } from 'node:os'
+import { createServer as createServerHttp } from 'node:http'
+import { fileURLToPath } from 'node:url'
+
+import './files/c.cjs'
+
+const random = Math.random()
+
+const unknownObject = await (random > 0.5
+	? import('./files/a.json', { with: { type: 'json' } })
+	: 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 = path.dirname(fileName)
+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/files/fileToWrite.txt

@@ -0,0 +1,12 @@
+rfgdfgdfgfd
+gdf
+gfd
+gfd
+g
+fdg
+fd
+g
+fdg
+
+
+

src/streams/read.js

@@ -1,5 +1,11 @@
+import { createReadStream } from 'fs'
+import path from 'path'
+
+const filePath = path.resolve(import.meta.dirname, 'files/fileToRead.txt')
+
 const read = async () => {
-  // Write your code here
-};
+	const readStream = createReadStream(filePath, 'utf8')
+	readStream.pipe(process.stdout)
+}
 
-await read();
+await read()