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

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

Arguments

Conteúdo do Curso

Introduction to JavaScript

Introduction to JavaScript

Arguments

Arguments are function variables that you can use only inside the function:


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function funcName(a, b) {
  console.log("Arg A =", a);
  console.log("Arg B =", b);
};

funcName(15, 24);

console.log(a);  // This will raise an Error

Also, if you name the arguments the same as the variables outside the function, the function will use the arguments instead of the variables:


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let a = 15;

function num(a) {
  console.log("(func) a =", a);
};

num(20);

console.log("(global) a =", a);

Note

When the function finishes execution, its space disappears, and all arguments lose their values.

Arguments are received sequentially:


              12345
            
function numSet(a, b, c) {
  console.log([a ** 2, b + 2, c - 10]);
};

numSet(15, 12, 99);

Unfilled arguments will receive the value undefined and will not be displayed in any way. Redundant arguments will not be used:


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function numSet(a, b, c) {
  console.log([a, b, c]);
}

numSet(12, 13);
numSet(15, 12, 13, 15);

The function receives values as arguments. Variables outside the function remain unchanged. An argument is an independent value inside a function:


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let a = 15;

function add(numb) {
  numb += 5;
  console.log("(func) numb =", numb);
};

add(a);

console.log("(global) a =", a);

Note

This does not work the same way for arrays because an array contains a reference to some data. This reference is passed to the function, so changes inside the function affect the data outside. This will be studied in the "OOP in JavaScript" course.

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Seção 6. Capítulo 4

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