What are default parameters and how are they used?

Default parameters in JavaScript allow you to set default values for function parameters if no value or undefined is passed. This helps avoid undefined values and makes your code more robust. You can define default parameters by assigning a value to the parameter in the function definition.

function greet(name = "Guest") {
  console.log(`Hello, ${name}!`);
}

greet(); // Output: Hello, Guest!
greet("Alice"); // Output: Hello, Alice!