Default parameters with types in Typescript - Mini Project: Build & Apply

Default parameters with types

📖 Scenario: You are creating a simple greeting function for a website. Sometimes users provide their name, and sometimes they don't. You want to make sure the function works well in both cases.

🎯 Goal: Build a TypeScript function called greet that takes a name parameter with a default value and a type. The function should return a greeting message.

📋 What You'll Learn

Create a function named greet with a parameter name of type string

Set the default value of name to "Guest"

Return a greeting string using the name parameter

Call the function twice: once without arguments and once with the argument "Alice"

Print the results of both calls

💡 Why This Matters

🌍 Real World

Default parameters help make functions flexible and easier to use when some information is optional.

💼 Career

Understanding default parameters with types is important for writing clean, safe, and maintainable TypeScript code in real projects.

1

Create the greet function with a typed name parameter

Write a function called greet that takes one parameter named name of type string. Do not add a default value yet.

Typescript

function greet(name: string) {
  // Your code here
}

Need a hint?

Use function greet(name: string) to define the function and return a greeting string using backticks.

2

Add a default value "Guest" to the name parameter

Modify the greet function so that the name parameter has a default value of "Guest".

Typescript

function greet(name: string = "Guest") {
  return `Hello, ${name}!`;
  // Your code here
}

Need a hint?

Add = "Guest" after the parameter name: string to set the default.

3

Call greet twice: once without arguments and once with "Alice"

Write two lines: call greet() without arguments and store the result in greeting1, then call greet("Alice") and store the result in greeting2.

Typescript

function greet(name: string = "Guest") {
  return `Hello, ${name}!`;
}

const greeting1 = greet();
const greeting2 = greet("Alice");
// Your code here

Need a hint?

Use const greeting1 = greet() and const greeting2 = greet("Alice") to call the function.

4

Print the greetings stored in greeting1 and greeting2

Write two console.log statements to print greeting1 and greeting2.

Typescript

function greet(name: string = "Guest") {
  return `Hello, ${name}!`;
}

const greeting1 = greet();
const greeting2 = greet("Alice");

console.log(greeting1);
console.log(greeting2);
// Your code here

Need a hint?

Use console.log(greeting1) and console.log(greeting2) to show the greetings.