Nested Function

Lesson 7 of 14 in Coddy's Function Declarations in JavaScript course.

Nested functions are like superheroes with sidekicks – they're powerful functions that can create and use other functions within them.

A nested function is a function defined inside another function. The inner function has access to the outer function's variables and parameters, creating a local scope within the outer function.

Imagine you have a main function (the superhero) that needs help with a specific task. Instead of relying on an external function, it can create a helper function (the sidekick) within itself to handle that specific task. This helper function can only be accessed and used by the main function. For Example:

function calculateDiscount(originalPrice, discountPercentage) {
  	function calculateDiscountAmount(price, discount) {
    	return price * discount; // Calculate discount amount (inner function)
  	}

  	const discountAmount = calculateDiscountAmount(originalPrice, discountPercentage / 100);
  	const finalPrice = originalPrice - discountAmount;
  	return finalPrice;
}

const discountedPrice = calculateDiscount(100, 20);
console.log(discountedPrice); // Output: 80

Outer Function:
- We define a function named calculateDiscount that takes two arguments: originalPrice and discountPercentage.
Inner Function:
- Inside the outer function, we define another function named calculateDiscountAmount. This is the nested function. It takes two arguments: price and discount (notice it doesn't have access to originalPrice or discountPercentage directly).
Output: The function returns the final price, which is 80 (after applying the 20% discount).

Challenge

Easy

Your task is to create a nested function named calculateTaxAmount should takes the price and taxRate from the outer function calculateWithTax and Calculates tax amount and returns it. (The tax amount is the price multiplied by the tax rate)

Finally, the outer function should calculate and return the final price (including tax) by adding the tax amount to the original price and returns final price.

Try it yourself

function calculateWithTax(product) {
    let price = product.price;
    let taxRate = product.taxRate;
   // write code here
}

All lessons in Function Declarations in JavaScript

1Course Introduction

What you will learn?

4Milestone Challenges

Check Number State Greetings with Arrow Function Grading System

2Introduction to Functions

What is Function?Pure Functions Function Exercise #1 Function Exercise #2

3Ways of Function Declaration

Basic FunctionNested FunctionReturning a Function Function Expressions Arrow Function Function Constructor