Course Content

Introduction to JavaScript

1. JavaScript Fundamentals

About JavaScript Understanding JavaScript Syntax Challenge: Console Output in JavaScript Using Comments to Document Code Challenge: Write a Single-Line Comment Challenge: Write a Multi-Line Comment

2. Variables and Data Types in JavaScript

Understanding Variables in JavaScript Challenge: Define the Variable Using const for Constants Exploring JavaScript Data Types Working with null in JavaScript Introduction to Arrays Array Methods and Manipulation Challenge: Perform Array Operations

3. Performing Operations in JavaScript

Understanding Assignment Operators Mathematical Operations in JavaScript Assignment Operators in JavaScript Increment and Decrement Operators Challenge: Variable Operations Practice Comparison Operators in JavaScript Logical Operators Explained Challenge: Compare Variables in JavaScript Concatenating Strings in JavaScript Challenge: Build Sentences with JavaScript

4. Controlling Program Flow with Conditional Statements

Mastering if Statements in JavaScript Using else for Alternative Outcomes Applying else if for Multiple Conditions Challenge: Determine Sizes with Conditionals

5. Looping Through Data in JavaScript

Understanding the while Loop in JavaScript Using the do while Loop for Iteration Challenge: Print Numbers from 5 to 9 Mastering the for Loop in JavaScript Challenge: Console Tigers with Loops Breaking Out of Loops with break Skipping Iterations with continue Challenge: Stop and Skip in Loops

6. Functions in JavaScript

What Are Functions in JavaScript?Defining Functions in JavaScript Challenge: Write a Function – My Name Using Function Arguments Effectively Returning Values from Functions Challenge: Create a Sum Function Course Summary & Next Steps

Exploring JavaScript Data Types

Data can be represented in various ways, and the operations you perform on data can differ depending on the data types.

Note

The Data Type tells the interpreter how to work with the data.

Let's look at the difference in the interpreter behavior:


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// First case
console.log("123" + "123");

// Second case
console.log(123 + 123);

In the example above, you can see that the interpreter performs different operations for different data types.

typeof()

The typeof() operator returns a string indicating the type of the operand's value.


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let a = 15;
console.log(typeof 23);
console.log(typeof a);

const b = "today";
console.log(typeof "word");
console.log(typeof b);

Number

The number data type is used for calculations, counters, mathematical operations, and more.

Unlike other programming languages, JavaScript uses the number type instead of separate int and float types.


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console.log(typeof(15.25));
console.log(typeof(211));

console.log(typeof(22 + 251));
console.log(typeof(26 / 342));

Note

The typeof operator only determines the data type of the result, not the performed operations.

String

The string data type is used to change, print, and pass text to other programs.


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let str = "Hello! I'm String, and I should help you to work with text!";
console.log(str);

To identify the string in the code, we should use single or double quotes (e.g., 'some text' or "some text")


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console.log("text");
console.log('text');

console.log("console.log('text')");
console.log('console.log("text")');

console.log(typeof("10"));

Note

Choose one quote style ("text" or 'text') for your code or project;

You can switch between quote styles when using ' or " within the text, such as "She hasn't hat" or 'He says "Hi!"'.

Boolean

The boolean data type is used for logical operations. It has two values: true and false. Booleans are used to check conditions, as we'll describe later.

Booleans allow you to control code execution and direct it along different paths.

To create a boolean value, use the true or false values:


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console.log(true);
console.log(false);

console.log(typeof(true));
console.log(typeof(false));

console.log(25 > 15);
console.log(15 > 25);

Everything was clear?

Thanks for your feedback!

Section 2. Chapter 4

Introduction to JavaScript

Exploring JavaScript Data Types

typeof()

Number

String

Boolean

1. The `true` and `false` are ___.

2. What is the data type of the value `"number"`?

3. What is the data type of the value `15`?

4. What is the data type of the value `19.32`?

5. What is the data type of the value `true`?

6. Drag values to their types.

Introduction to JavaScript

Exploring JavaScript Data Types

typeof()

Number

String

Boolean

1. The true and false are ___.

2. What is the data type of the value "number"?

3. What is the data type of the value 15?

4. What is the data type of the value 19.32?

5. What is the data type of the value true?

6. Drag values to their types.

1. The `true` and `false` are ___.

2. What is the data type of the value `"number"`?

3. What is the data type of the value `15`?

4. What is the data type of the value `19.32`?

5. What is the data type of the value `true`?