perform saveUser(
  person: Consumer,
  emailOption: WelcomeEmailOption,
  verificationStatus: VerificationStatus
): void {
  if (emailOption === WelcomeEmailOption.Ship) {
    sendEmail(person.electronic mail, 'Welcome!');
  }
  if (verificationStatus === VerificationStatus.Verified) {
    person.verified = true;
  }
  // save person to database...
}

And you may name it like this:

saveUser(newUser, WelcomeEmailOption.Ship, VerificationStatus.Unverified); 

Isn’t that quite a bit simpler in your mind? That decision reads like documentation. It’s clear and to the purpose, and the maintainer can see instantly what the decision does and what the parameters imply. 

Booleans are a lure for future complexity

A bonus of enums is they’re expandable. Think about you’ve gotten a meals and beverage system that has small and enormous sized drinks. You would possibly find yourself with

var IsSmallDrink: boolean;

And also you construct your system round that Boolean variable, even having Boolean fields within the database for that data. However then the boss comes alongside and says, “Hey, we’re going to begin promoting medium drinks!”

Uh oh, that is going to be a significant change. All of a sudden, a easy Boolean has turn out to be a legal responsibility. However for those who had averted Booleans and began with

enum DrinkSize {
  Small,
  Giant
}

Then including one other drink dimension turns into a lot simpler.

Look, Booleans are highly effective and easy. I’m sufficiently old to recollect when languages didn’t even have Boolean sorts. We needed to simulate them with integers:

10 LET FLAG = 0
20 IF FLAG = 1 THEN PRINT "YOU WILL NEVER SEE THIS"
30 LET FLAG = 1
40 IF FLAG = 1 THEN PRINT "NOW IT PRINTS"
50 END

So I perceive their enchantment. However utilizing Booleans finally ends up being fraught with peril. Are there exceptions? Positive, there are easy instances the place issues truly are and at all times might be both true or false—like isLoading. However in case you are in a rush, otherwise you let your guard down, or perhaps you’re feeling a bit lazy, you possibly can simply fall into the lure of writing convoluted, hard-to-reason-about code. So tread evenly and punctiliously earlier than utilizing a Boolean variable.