Node.js basics refactoring

package.json

@@ -11,8 +11,8 @@
     "fs:delete": "node ./src/fs/delete.js",
     "fs:list": "node ./src/fs/list.js",
     "fs:read": "node ./src/fs/read.js",
-    "cli:env": "RSS_CHOOL=!!! node ./src/cli/env.js",
-    "cli:args": "node ./src/cli/args.js --hello me",
+    "cli:env": "npx cross-env RSS_AWS=MAYBE RSS_NODEJS=DEFINETELY node ./src/cli/env.js",
+    "cli:args": "node ./src/cli/args.js --hello me --californian dream",
     "modules": "node ./src/modules/cjsToEsm.mjs",
     "hash": "node ./src/hash/calcHash.js",
     "streams:read": "node ./src/streams/read.js",

src/cli/env.js

@@ -1,16 +1,13 @@
 export const parseEnv = () => {
-    let variables = ''
-    for (const variable in process.env) {
-        if (variable.startsWith('RSS_')) {
-            const varWithVal = `${variable}=${process.env[variable]}`
-            if (!variables) {
-                variables = variables + varWithVal ;
-            } else {
-                variables = variables + '; ' + varWithVal;
-            }
+    const variables = Object.entries(process.env).reduce((accum, [key, value]) => {
+        if (key.startsWith('RSS_')) {
+            accum.push(`${key}=${value}`);
         }
-    }
-    console.log(variables);
+        return accum;
+    }, []);
+
+    const parsedVariables = variables.join('; ')
+    console.log(parsedVariables)
 };
 
 parseEnv();

src/cp/cp.js

@@ -1,12 +1,20 @@
 import { spawn } from 'child_process';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+
+// windows case just in case
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 export const spawnChildProcess = async (args) => {
-    const file = new URL('files/script.js', import.meta.url).pathname;
-    const ls = spawn('node', [file, ...args]);
-    process.stdin.pipe(ls.stdin);
+    const scriptProcess = spawn('node', [`${__dirname}/files/script.js`, ...args]);
+
+    process.stdin.on('data', (data) => {
+        scriptProcess.stdin.write('Master stdin: ' + data)
+    });
 
-    ls.stdout.on('data', (data) => {
-        console.log(`stdout: ${data}`);
+    scriptProcess.stdout.on('data', (data) => {
+        console.log(`Master stdout: Child stdout: ${data}`);
     });
 
 };

src/fs/copy.js

@@ -5,24 +5,13 @@ const customError = new Error('FS operation failed');
 export const copy = async () => {
     const files = new URL('files', import.meta.url);
     const files_copy = new URL('files_copy', import.meta.url);
-    fs.opendir(files_copy)
-        .then(() => {
-            console.error(customError);
-        })
-        .catch(err => {
-            if (err.code === 'ENOENT') {
-                fs.cp(files, files_copy, { recursive: true })
-                    .catch(err => {
-                        if (err.code === 'ENOENT') {
-                            //console.error(customError);
-                        } else {
-                            console.error(new Error(err))
-                        }
-                    })
-            } else {
-                console.error(err)
-            }
-        })
+
+    try {
+        await fs.mkdir(files_copy, { recursive: false });
+        await fs.cp(files, files_copy, { recursive: true })
+    } catch {
+        throw customError;
+    }
 };
 
 copy();

src/fs/create.js

@@ -1,19 +1,14 @@
 import * as fs from 'fs/promises';
 
+const customError = new Error('FS operation failed');
+
 export const create = async () => {
     const file = new URL('files/fresh.txt', import.meta.url);
-    fs.open(file)
-        .then(() => {
-            const err = new Error('FS operation failed');
-            console.error(err);
-        })
-        .catch(err => {
-            if (err.code === 'ENOENT') {
-                fs.writeFile(file, 'I am fresh and young');
-            } else {
-                console.error(err);
-            }
-        })
+    try {
+        await fs.writeFile(file, 'I am fresh and young', { flag: 'wx' });
+    } catch {
+        throw customError;
+    }
 };
 
 create();

src/fs/delete.js

@@ -4,17 +4,12 @@ const customError = new Error('FS operation failed');
 
 export const remove = async () => {
     const file = new URL('files/fileToRemove.txt', import.meta.url);
-    fs.readFile(file)
-        .then(() => {
-            fs.rm(file);
-        })
-        .catch(err => {
-            if (err.code === 'ENOENT') {
-                console.error(customError);
-            } else {
-                console.error(err);
-            }
-        })
+
+    try {
+        await fs.rm(file);
+    } catch {
+        throw customError;
+    }
 };
 
 remove();

src/fs/list.js

@@ -5,17 +5,12 @@ const customError = new Error('FS operation failed');
 export const list = async () => {
     const files = new URL('files/', import.meta.url);
 
-    fs.readdir(files)
-        .then(res => {
-            console.log(res);
-        })
-        .catch(err => {
-            if (err.code === 'ENOENT') {
-                console.error(customError);
-            } else {
-                console.error(err);
-            }
-        })
+    try {
+        const listOfFiles = await fs.readdir(files);
+        console.log(listOfFiles);
+    } catch {
+        throw customError;
+    }
 };
 
 list();

src/fs/read.js

@@ -4,17 +4,13 @@ const customError = new Error('FS operation failed');
 
 export const read = async () => {
     const file = new URL('files/fileToRead.txt', import.meta.url);
-    fs.readFile(file, 'utf8')
-        .then(res => {
-            console.log(res);
-        })
-        .catch(err => {
-            if (err.code === 'ENOENT') {
-                console.error(customError);
-            } else {
-                console.error(err);
-            }
-        })
+
+    try {
+        const fileContent = await fs.readFile(file, 'utf8');
+        console.log(fileContent);
+    } catch {
+        throw customError;
+    }
 };
 
 read();

src/fs/rename.js

@@ -5,17 +5,12 @@ const customError = new Error('FS operation failed');
 export const rename = async () => {
     const fileWrong = new URL('files/wrongFilename.txt', import.meta.url);
     const fileProper = new URL('files/properFilename.md', import.meta.url);
-    fs.readFile(fileProper)
-        .then(() => {
-            console.error(customError);
-        })
-        .catch(err => {
-            if (err.code === 'ENOENT') {
-                fs.rename(fileWrong, fileProper);
-            } else {
-                console.error(err)
-            }
-        })
+
+    try {
+        await fs.rename(fileWrong, fileProper);
+    } catch {
+        throw customError;
+    }
 };
 
 rename();

src/hash/calcHash.js

@@ -5,11 +5,12 @@ export const calculateHash = async () => {
     const file = new URL('files/fileToCalculateHashFor.txt', import.meta.url);
     const hash = crypto.createHash('sha256');
 
-    fs.readFile(file)
-        .then(res => {
-            hash.update(res);
-            console.log(hash.digest('hex'));
-        })
+    try {
+        const content = await fs.readFile(file);
+        console.log(hash.update(content).digest('hex'));
+    } catch (err) {
+        throw err;
+    }
 };
 
 calculateHash();

src/modules/cjsToEsm.mjs

@@ -8,11 +8,13 @@ const random = Math.random();
 let unknownObject;
 
 if (random > 0.5) {
-    unknownObject = import('./files/a.json', { assert: { type: 'json' } });
+    unknownObject = await import('./files/a.json', { assert: { type: 'json' } });
 } else {
-    unknownObject = import('./files/b.json', { assert: { type: 'json' } });
+    unknownObject = await import('./files/b.json', { assert: { type: 'json' } });
 }
 
+console.log(unknownObject)
+
 console.log(`Release ${release()}`);
 console.log(`Version ${version()}`);
 console.log(`Path segment separator is "${path.sep}"`);

src/streams/read.js

@@ -1,11 +1,19 @@
-import fs from 'fs';
+import fs from 'fs/promises';
+import Stream from 'stream';
 import { stdout } from 'process';
 
 export const read = async () => {
     const file = new URL('files/fileToRead.txt', import.meta.url);
+    const readableStream = new Stream.Readable();
+    readableStream._read = () => {};
 
-    const stream = fs.createReadStream(file);
-    stream.pipe(stdout);
+    try {
+        const content = await fs.readFile(file);
+        readableStream.push(content);
+        readableStream.pipe(stdout);
+    } catch (err) {
+        throw err;
+    }
 };
 
 read();

src/streams/transform.js

@@ -1,17 +1,24 @@
 import { stdout, stdin } from 'process';
-import { Transform } from 'stream';
+import { Transform, pipeline } from 'stream';
 
 export const transform = async () => {
-    class UppercaseTransform extends Transform {
+    class ReverseTransform extends Transform {
         constructor(options) {
             super(options);
         }
 
-        _transform(chunk) {
-            this.push(Buffer.from([...chunk].reverse()).toString());
+        _transform(chunk, e, callback) {
+            callback(null, Buffer.from([...chunk].reverse()).toString());
         }
     }
-    stdin.pipe(new UppercaseTransform()).pipe(stdout);
+    const reverse = new ReverseTransform();
+
+    pipeline(
+        stdin,
+        reverse,
+        stdout,
+        (err) => { throw err; }
+    )
 };
 
 transform();

src/wt/main.js

@@ -1,7 +1,7 @@
 import os from 'os';
 import { Worker } from 'worker_threads';
 
-const creator = (i) => new Promise((resolve, reject) => {
+const workerCreator = (i) => new Promise((resolve, reject) => {
     const file = new URL('./worker.js', import.meta.url);
     const worker = new Worker(file, {
         workerData: 10 + i
@@ -16,7 +16,7 @@ export const performCalculations = async () => {
 
     for (let i = 0; i < cpuData.length; i++) {
         try {
-            const data = await creator(i);
+            const data = await workerCreator(i);
             arrResults.push(
                 {
                     status: 'resolved',

src/wt/worker.js

@@ -4,7 +4,6 @@ export const nthFibonacci = (n) => n < 2 ? n : nthFibonacci(n - 1) + nthFibonacc
 
 export const sendResult = () => {
     parentPort.postMessage(nthFibonacci(workerData));
-    process.exit();
 };
 
 sendResult();

src/zip/compress.js

@@ -14,8 +14,7 @@ export const compress = async () => {
 
     pipeline(source, gzip, destination, (err) => {
         if (err) {
-            console.error(err);
-            process.exitCode = 1;
+            throw err;
         }
     });
 };

src/zip/decompress.js

@@ -14,8 +14,7 @@ export const decompress = async () => {
 
     pipeline(source, gunzip, destination, (err) => {
         if (err) {
-            console.error(err);
-            process.exitCode = 1;
+            throw err;
         }
     });
 };