Guard Clauses

Guard clauses, also known as guard statements or early returns, are a programming pattern used in JavaScript (and other programming languages) to improve code readability and reduce the nesting of conditionals. They involve checking for certain conditions at the beginning of a function and immediately returning or taking some action if those conditions are met. This helps to simplify the structure of the code and handle exceptional cases early, rather than having deep nested blocks of code.

Guard clauses are particularly useful when you want to handle edge cases, error conditions, or scenarios that don’t fit the main flow of the function. By handling these cases first, you avoid unnecessary nesting and improve the overall readability of the code.

function userIsAdmin(user) {
	if (user.role == "admin") {
		if (user.manager == true) {
			return true;
		} else {
			return false;
		}
	} else {
		return false;
	}
}

Refactor the previous example to Guard clauses:

function userIsAdmin(user) {  
	if (user.role != 'admin') return false  
	if (user.manager != true) return false  
	return true  
}

Advantages of using guard clauses:

• Improved Readability: By handling exceptional cases at the beginning of the function, the main logic becomes more prominent and easier to understand.

• Reduced Nesting: Guard clauses eliminate the need for deeply nested if statements, which can improve code readability and maintainability.

• Easier Debugging: When an exceptional case occurs, guard clauses provide an immediate exit point, making it easier to identify and debug issues.

• Modular Code: Guard clauses make it clear how different conditions are handled, which can make it easier to modify or extend the function in the future