JAVASCRIPT FUNDAMENTALS

Question:

In what scenarios should one use if..else statements and in what scenarios should one switch statements in JavaScript?

Any help will be appreciated.
Happy Coding

Comments

[J. G. Sebring]

By it's nature switch only compares the value of a single variable.

Generally a switch works best when comparing the value/state of a single variable against a known set of possibilities. Think of incoming keystroke and you want to act differently depending on what key is pressed. A switch here makes much more sense than multiple if/else.

switch(key.value) {
 case 'a':
  // do something...
  break
 case 'b':
  // do something else...
  break
 // etc
}

If you are comparing different variables - rather than one single, maybe also using functions as conditions, a switch statement would not be appropriate at all - if even possible.

Sample pseudo code for a login to validate username and password.

signup(username, password) {
 let errorMessage = ''
 if (username.length < 3 && username.length > 12)
  errorMessage = `Username must be at least 4 chars long but no longer than 12.`
 else if (isUsernameTaken(username)) 
  errorMessage = `Username is already taken.`
 else if (isPasswordTooWeak(password))
  errorMessage = `Password must bla bla`

 if (errorMessage)
  alert(errorMessage)
 else
  createUser(user, password)

I generally consider a lot of trailing if else as bad practice and try to solve things with a different approach, depending on situation. I think it is pain to maintain, can be hard to follow and bug prone. A switch statement however are usually pretty straight forward, just avoid magic numbers/strings and use constants, enums or similar instead.
Happy coding!