add: non blocking io

node-concepts/src/js-general/non-blocking-io/async-sync.js

@@ -0,0 +1,58 @@
+const fs = require('fs');
+const path = require('path');
+
+/** @internal */
+function syncFunction() {
+	console.log('Synchronous function is executed!');
+}
+
+// Asynchronous function outside main
+async function outsideAsyncFunction() {
+	console.log('Outside async function started. ===> 2️⃣');
+	await delay(1000); // Simulate some async work
+	console.log('Outside async function finished after 1 second. 2️⃣');
+}
+// Asynchronous function that reads a file
+async function readFileAsync(filePath) {
+	return new Promise((resolve, reject) => {
+		fs.readFile(filePath, 'utf8', (err, data) => {
+			if (err) {
+				reject(err);
+			} else {
+				resolve(data);
+			}
+		});
+	});
+}
+
+async function delay(ms) {
+	return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+/**
+ * ## Main
+ * - The await inside the main function does not block functions outside of main.
+ * - It only pauses the execution of the main function itself until the promise resolves,
+ * - but it does not block the entire Node.js event loop.
+ */
+async function main() {
+	console.log('Main function started. ==> 1️⃣');
+
+	console.log('Before file read... 1️⃣');
+	try {
+		const fileContent = await readFileAsync('file1.txt');
+		console.log('File Content: Finished... 1️⃣');
+	} catch (err) {
+		console.error('Error reading file:', err);
+	}
+
+	console.log('Waiting for 2 seconds... 1️⃣');
+	await delay(2000);
+	console.log('2 seconds passed. 1️⃣');
+
+	console.log('Main function finished. ==> 1️⃣');
+}
+
+main();
+
+outsideAsyncFunction();

node-concepts/src/js-general/non-blocking-io/file-read.js

@@ -0,0 +1,19 @@
+const fs = require('fs');
+
+fs.readFile('file1.txt', 'utf8', (err, data1) => {
+	if (err) {
+		console.error('Error reading file1:', err);
+		return;
+	}
+	console.log('File1 content:', data1);
+});
+
+fs.readFile('file2.txt', 'utf8', (err, data2) => {
+	if (err) {
+		console.error('Error reading file2:', err);
+		return;
+	}
+	console.log('File2 content:', data2);
+});
+
+console.log('Files are being read concurrently.');