Lesson 2.2: Arrow Functions & Review

Table of Contents

1. Arrow Functions
2. Single Parameter
3. Multiple Parameters

Arrow Functions

What is a function?

In programming, a function is a reusable block of code that performs a specific task. Functions help organize your code, make it more readable, and reduce redundancy.

Why do we use functions in programming?

• Modularity: Functions allow you to break down complex problems into smaller, manageable tasks.
• Reusability: You can use the same function in multiple parts of your code.
• Readability: Functions make your code more organized and easier to understand.

Quick Recap

Arrow functions provide a concise syntax to write functions in JavaScript. They are declared with the following structure:

const functionName = () => {
  // Your code here
}

Here's an example:

const greet = () => {
  console.log('Hello!');
}

You can often convert a regular function into an arrow function. For example:

// Regular function
function greet() {
  console.log('Hello!');
}

// Arrow function
const greet = () => {
  console.log('Hello!');
}

Code Along

Use the arrow.js file to complete the tasks. As you code, make sure you are following along with the examples provided in the lesson.

Single Parameter

In this section, you'll learn about functions that take a single parameter.

Function Declaration with Parameters

To declare a function with a parameter, use the following syntax:

function functionName(parameterName) {
  // Your code here
}

Here's an example:

function squareNum(num) {
  return num * num;
}

Function Call with Arguments

When calling a function with parameters, you provide arguments. Arguments are the actual values that you want to use inside the function. For example:

squareNum(7); // Calling squareNum with the argument 7
squareNum(6); // Calling squareNum with the argument 6

let userInput = input.value; // Assuming input.value holds a number
squareNum(userInput); // Calling squareNum with a variable as the argument

Multiple Parameters

Functions can also take multiple parameters.

function greet(name1, name2) {
  console.log(`Hi ${name1} & ${name2}!`);
}

Multiple Parameters - Order Matters

When using multiple parameters, it's important to place the arguments in the right order when you call the function. The order of the arguments should match the order of the parameters in the function declaration.

greet("Lucy", "Pablo"); // Correct order

Happy coding 😊