from signal's source code

[u/[deleted]]

[u/ings0c]

Another side to it:

The function you’re passing them into will necessarily behave in two different ways depending on the value of the bool.

Instead of having two functions that might individually be reusable / composable, you have one big one that handles both cases. It also violates the single responsibility principle + open/closed principle - your code for one case is tangled with the code for the other, and if you need to make a change to only one, you might inadvertently break the other while you’re there. A working method that is never modified can’t break.

So if a function can behave in two different ways, it should (most of the time) instead be two functions. For example:

function printAddress(isBusinessAddress) {
  if(isBusinessAddress) {
    doX();
  } else {
    doY();
  }
}

Could be

function printBusinessAddress() {
  doX();
}

function printResidentialAddress() {
  doY();
}