Nested If - Else

Part of the Fundamentals section of Coddy's JavaScript journey — lesson 26 of 77.

We can nest if-else if-else statements within each other. This allows us to create hierarchical decision-making structures.

For example:

let result;
if (age > 18) {
    if (has_license) {
        result = "You can drive";
    } else {
        result = "Get a license first";
    }
} else {
    result = "Too young to drive";
}

It can be infinite nested:

if (condition1) {
	// if condition1 is true
	if (condition2) {
		// if condition1 and condition2 are true
		if (condition3) {
		    // if condition1, condition2 and condition3 are true
		    ...
		}
	}
}

Challenge

Create a program that checks if someone can enter a swimming pool.

Rules:

Must be at least 10 years old
If they are under 13, they must have an adult with them

Print exactly these messages:

If too young:
Sorry, you are too young
If under 13 and no adult:
Sorry, you need an adult with you
If under 13 with adult:
You can enter with adult supervision!
If 13 or older:
You can enter by yourself!

Cheat sheet

You can nest if / else statements to make step-by-step (hierarchical) decisions:

let result;
if (age > 18) {
    if (has_license) {
        result = "You can drive";
    } else {
        result = "Get a license first";
    }
} else {
    result = "Too young to drive";
}

Nesting means putting one condition inside another:

if (condition1) {
    if (condition2) {
        if (condition3) {
            // All conditions are true
        }
    }
}

Use nesting when each check depends on the previous one being true.

Try it yourself

let age = parseInt(inp[0]); // Don't change this line
let has_adult = inp[1] === "true"; // Don't change this line

// Write your code below

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

The Language Hello World!Comments Code Structure

4Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Type Coercion

7Bill Split Calculator

Welcome Message Calculating The Tip And Total

Splitting The Bill

Formatted Output

10FizzBuzz with a Twist

Game Overview The FizzBuzz Function

Looping The Numbers

Adding The Twist

13Grocery List Tracker

Project Overview Add Item

Remove Item

View List

2Variables

Numbers String Boolean Naming Conventions Empty Variables Recap - Initialize Variables Constants

5Decision Making

If Statement If - Else Recap - Simple CalculatorNested If - ElseSwitch Statement

8Loops

For Loop While Loop Break Continue Recap - Factorial Do While Loop Nested Loop

11Arrays Part 1

Declaring an Array Accessing Array Elements Modifying Arrays Array Methods Part 1 Array Methods Part 2 Recap - Array Processor

14Final Challenges

Number Pyramid Double The Odds What To Buy