Would variables declared in an `if` statement be accessible directly outside the `if` statement?

Frequently Asked Questions JavaScript FAQ
1

Question

Would variables declared in an if statement be accessible directly outside the if statement?

Answer

No, variables declared inside an if statement would not be accessible directly outside an if statement because if statements have their own scope. How might you set a value based on a conditional then? You can either use a ternary operator or declare the variable outside the if/else statement and define the variables value inside the if/else.
This does not work:

    	let capacity = 50;
    	let numberOfPeople = 80;
    	if(numberOfPeople > capacity) {
    		let numberOfExtraPeople = numberOfPeople - capacity;
    	}
    	else {
    		let numberOfExtraPeople = 0;
    	}
    	// Prints undefined because numberOfExtraPeople is not in this scope
    	console.log(numberOfExtraPeople);

However, this works:

    	let capacity = 50;
    	let numberOfPeople = 80;
    	let numberOfExtraPeople;
    	if(numberOfPeople > capacity) {
    		numberOfExtraPeople = numberOfPeople - capacity;
    	}
    	else {
    		numberOfExtraPeople = 0;
    	}
    	// Prints 30 because numberOfExtraPeople was declared in the same scope as the console.log
    	console.log(numberOfExtraPeople);