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

Logical Operators Explained

Now, let's explore logical operations. Logical operations are used to manipulate and make decisions based on boolean values.

Logical Operators

There are three logical operators in JavaScript:

AND (&&);
OR (||);
NOT (!).

AND (&&)

The AND (&&) logical operator returns true only when both values it operates on are true. The result is false if any value is false.


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

The AND (&&) operator requires all values to be true to return true.

OR (||)

The OR (||) logical operator returns true if at least one of the values is true. It returns false only when both values are false.


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

The OR (||) operator returns false only when both values are false.

NOT (!)

The NOT (!) operator inverts the boolean value. It turns true into false and false into true.


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

Using Logical Operators

Logical operators are often used to combine conditions. For example, to check if two values are greater than 4 or greater than 1, you can use the AND (&&) operator.


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let a = 5, b = 3;

console.log(a > 4 && b > 4);
console.log(a > 1 && b > 1);

Priority

Logical operations have a lower priority than comparison operations, which, in turn, have a lower priority than mathematical operations.

Note

Similar to other operations, you can use parentheses () to adjust the priority of execution.

1. What will be the output?

2. What will be the output?

3. What will be the output?

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Section 3. Chapter 7