gistfile1.md

When a beginner asks you "when do I use semi-colons?" would you rather say this?

// what people who say "use semicolons!!" say
class Foo {
  prop = {
  }; // yes

  static bar () {
    if (stuff) {
      doStuff(); // yes
    } // no

    for (var key in obj) {
    } // no

    return {
    }; // yes
  } // no

  foo () {
  } // no
} // no

Foo.prop = {
}; // yes

things.map(thing => thing.name /*no*/)

var boing = function () {
}; // yes

function boing () {
} // no

/*no*/[1,2,3].map(); // yes
/*no*/(function () {})(); // yes

Or this?

// what people who say "don't use semicolons!" say
/*yes*/;[1,2,3].map()
/*yes*/;(function () {})()
// which are two things I haven't done in the last 3 years, mind you

In the end, I'd rather not talk about semi-colons, and just do what people around me want me to do, but when teaching a beginner who asks (and they ALWAYS ask this) "when do I use a semi-colon", I just put my face in my hands and say "I don't have any answers for you".

I would add one extra rule: Never write a return statement without a value following it. So ban this:

return

and always write one of.

return undefined
return null
return 0
return someValue

This is an improvement over the always write semi-colons approach.

When you always write semi-colons, it makes you think this would work correctly:

return
  {a: 1}

However, if you don't write unnecessary semi-colons, you're already used to treating lines as statements, and are much less likely to do this.