JS Basics - Class II

Lecture 39 :- JS Basics - Class II

In "JS Basics - Class II," we'll continue exploring fundamental JavaScript concepts, including arrays, objects, functions, and more advanced topics like loops and conditional statements. Let's dive deeper:

Arrays: Arrays are used to store multiple values in a single variable. They are indexed starting from 0 and can hold different data types.

Accessing array elements:

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console.log(numbers[0]); // Output: 1 console.log(fruits[1]); // Output: "banana"

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let numbers = [1, 2, 3, 4, 5]; let fruits = ["apple", "banana", "orange"]; let mixedArray = [1, "hello", true, null];

Objects: Objects allow you to store data in key-value pairs. Keys are strings that act as identifiers for values.

Accessing object properties:

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console.log(person.name); // Output: "Alice" console.log(person.age); // Output: 25

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let person = {  name: "Alice",  age: 25,  isStudent: true, };

Functions (Continued): Functions can take parameters and return values.

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function add(a, b) {  return a + b; } let result = add(3, 5); // Output: 8

Conditional Statements (Continued): You can use logical operators (&&, ||, !) and ternary operator (? :) for more complex conditions.

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let age = 25; let isStudent = true; if (age >= 18 && isStudent) {  console.log("You are an adult student."); } else if (age >= 18) {  console.log("You are an adult."); } else {  console.log("You are a minor."); }

Loops (Continued): Loops can be used to iterate over arrays or objects.

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// For loop for (let i = 0; i < numbers.length; i++) {  console.log(numbers[i]); } // For...of loop (for arrays) for (let num of numbers) {  console.log(num); } // For...in loop (for objects) for (let key in person) {  console.log(key + ": " + person[key]); }

Scope: JavaScript has two types of scope: global scope and local scope. Variables declared with let and const have block-level scope.

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let globalVar = "I'm global"; // Global scope function exampleFunction() {  let localVar = "I'm local"; // Local scope  console.log(globalVar); // Accessible  console.log(localVar); // Accessible } exampleFunction(); console.log(globalVar); // Accessible // console.log(localVar); // Error: localVar is not defined (out of scope)

Arrow Functions: Arrow functions provide a shorter syntax for defining functions.

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// Traditional function function sayHello(name) {  return "Hello, " + name + "!"; } // Arrow function let greet = (name) => "Hello, " + name + "!"; console.log(sayHello("Alice")); // Output: "Hello, Alice!" console.log(greet("Bob")); // Output: "Hello, Bob!"

This class builds on the concepts covered in "JS Basics - Class I" and introduces you to more complex programming structures in JavaScript. As you continue your JavaScript journey, you'll learn about advanced topics like closures, asynchronous programming, classes, and more.

Remember to practice coding regularly and work on small projects to reinforce your understanding of JavaScript. If you have any specific questions or need further clarification on any topic, feel free to ask! Happy coding!