Hacker News Reader

Comment by evanmoran | Hacker News Reader

I find they are useful for shortcutting out of functions:

    throw 'error' if badness
    
    return null unless goodness

Since it doesn't make sense to return or throw unconditionally it is makes it pretty clear that you should look for the if/unless.

View on HN

Though, what's the benefit of putting the conditional after? I find these:

    if badness throw 'error'

    unless goodness return null

to be more readable

It's definitely nice to see the return at the beginning of the line -- makes the code easier to scan.

And anytime there's code after a return, it had better be connected to a conditional. :)

Those are good points. I'd probably make it multi-line:

    if badness
      throw 'error'
    
    unless goodness
      return null

If may be strange because of the asymmetry but I'd actually prefer `if` to be come first all the time and `unless` to come last all the time - precisely because `unless` reads like it's for exceptional circumstances:

  value = cache[key]
  if value?
    return value

  return file.readContents() unless not file.exists()

Reply on news.ycombinator.com