JavaScript fundamentals

JavaScript Fundamentals

JavaScript fundamentals lay the groundwork for understanding the language's core concepts, including variables and data types, operators and expressions, and control flow structures.

Variables and Data Types:

In JavaScript, variables are containers for storing data values. Variables can hold various types of data, including numbers, strings, booleans, arrays, objects, and more. Here's an example of declaring and initializing variables:

// Variable declaration and initialization

let name = "John";

let age = 30;

let isStudent = true;

let fruits = ["apple", "banana", "orange"];

let person = { firstName: "John", lastName: "Doe" };

Operators and Expressions:

Operators in JavaScript allow you to perform operations on variables and values. JavaScript supports various types of operators, including arithmetic, assignment, comparison, logical, and bitwise operators. Expressions are combinations of variables, values, and operators that evaluate to a single value. Here are some examples:

// Arithmetic operators

let sum = 5 + 3;

let difference = 10 - 5;

let product = 3 * 4;

let quotient = 20 / 5;

// Comparison operators

let isEqual = (5 === 5); // true

let isNotEqual = (10 !== 5); // true

let isGreater = (10 > 5); // true

let isLess = (3 < 10); // true

// Logical operators

let isLoggedIn = true;

let isAdmin = false;

let canAccessAdminPanel = isLoggedIn && isAdmin; // false

Control Flow: if Statements, Loops, and Switch Statements:

Control flow structures allow you to control the execution flow of your JavaScript code. if statements are used to make decisions based on conditions. Loops, such as for and while, are used to execute a block of code repeatedly. Switch statements provide a way to execute different actions based on different conditions. Here are examples of each:

// if statement

let hour = 10;

if (hour < 12) {

  console.log("Good morning!");

} else {

  console.log("Good afternoon!");

}

// for loop

for (let i = 0; i < 5; i++) {

  console.log("Iteration: " + i);

}

// while loop

let count = 0;

while (count < 3) {

  console.log("Count: " + count);

  count++;

}

// switch statement

let day = "Monday";

switch (day) {

  case "Monday":

    console.log("Today is Monday.");

    break;

  case "Tuesday":

    console.log("Today is Tuesday.");

    break;

  default:

    console.log("Today is not Monday or Tuesday.");

}

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