Introduction to JavaScript

Introduction to JavaScript

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1. Basic Concepts

Discover the fundamentals of JavaScript, including its purpose and syntax. Learn how to work with the console for output and use comments to organize and document your code. These foundational skills will prepare you for a deeper exploration of JavaScript's capabilities.

About JavaScript

Challenge: Console Output

Challenge: Single-line Comment

Challenge: Multi-line Comment

2. Variables and Data Types

Explore the building blocks of JavaScript by distinguishing between literals and variables. Understand the core data types, including `null` and arrays, and learn how to manipulate them using array methods.

Challenge: Defining the Variable

Data Types Overview

Array

Challenge: Array Operations

3. Basic Operations

Learn how to manipulate JavaScript's data types through essential operations. Master assignment, mathematical operations, incrementing and decrementing, comparisons, logical operations, and string concatenation.

Mathematical Operations

Operations with Assignment

Increment and Decrement

Challenge: Variable Operations

Comparison Operations

Logical Operations

Challenge: Comparing Variables

String Concatenation

Challenge: Sentence Building

4. Conditional Statements

Discover how to control the flow of your programs with conditional statements. Master `if`, `else`, and `else if` to instruct JavaScript on making decisions and executing code based on different conditions.

Challenge: Determining Size

5. Loops

Streamline your code by mastering JavaScript's looping structures. Explore `while`, `do while`, and `for` loops, and learn how to control their behavior using `break` and `continue`. Unlock the power of loops to perform repetitive tasks efficiently.

Challenge: Printing Numbers from 5 to 9

Challenge: Tigers

Challenge: Stopping and Skipping

6. Functions

Discover the power of functions in JavaScript. Learn how to define functions, work with arguments, and use the `return` statement to create reusable and efficient code. Mastering functions will enhance your ability to write clean and modular programs.

What is a Function?

Challenge: My Name

Conteúdo do Curso

Introduction to JavaScript

Introduction to JavaScript

Array

The array is the most useful data structure.

Note

A data structure is a specialized format for organizing and working with data collection. An array is a collection of items where each item is a value.

Creating an Array

To create an array, use square brackets []:

This creates an empty array with no elements. To create an array with elements, place the elements inside [] and separate them with commas (,):

Note

The last element in the array should not have a comma after it.

To print an array, simply use console.log():


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const arr = [1, 2, 3, 4, 5];

console.log(arr);

Indexes

Each element in an array has a unique index.

Note

Indexes start from 0. The first element has an index of 0, the second element has an index of 1, and so on.

Accessing array data is done by specifying the index in square brackets ([index]) after the array name:


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const arr = [1, 2, 3, 4, 5];

const thirdElement = arr[2];  // retrieving the 3rd element

console.log(thirdElement);

Arrays can hold different data types, including number, string, boolean, and more.


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const arr = [2441.23, "Hello!", false];

console.log(arr[0]);
console.log(arr[1]);
console.log(arr[2]);

Length Property

The length property is a built-in property of arrays that represents the number of elements in that array. To use this property, use the following syntax:


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const arr1 = [10, 20, 30];
const arr2 = [15, 25, 35, 45, 55];

const x = arr1.length; // `x` variable represents the `arr1` length
const y = arr2.length; // `y` variable represents the `arr2` length

console.log(x);
console.log(y);

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Seção 2. Capítulo 6

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