Semicolons in JavaScript are optional

Re:Semicolons in JavaScript are optional by axod on Friday June 25, 2010 @04:15AM (#1460293)

Use semicolons. Always. It's looks cleaner, and you won't come up against stupid errors like

  return
  {
     foo: 7
  }

From the article -

  When you're done trying to wrap your brain around
  why would anyone in their right mind want to write
  a return statement on a new line

Well, if they love having { on newlines, then it's pretty obvious:

  function foo()
  {
      return
      {
          bar: 8
      }
  }

From the article -

  That's 24 bytes right there. Stamp semicolons
  everywhere and run it through a minifier:

  var a=1;var b=2;var c=3;

Yeah um, hate to break it to you, but a minifier (and any experienced coder) would write it as "var a=1,b=2,c=3;"

  // after minification
  if(condition){stuff()}

Wrong again. Use a better minifier. Closure advanced mode for example will remove the {}, inline functions if it makes sense and hundreds of other things.

  Easy solution: when a line starts with parenthesis,
  prepend a semicolon to it.

  ;(d + e).print()

Ugly horrible hacky advice.

I remember when I first saw C code (coming from BASIC) and thought similar thoughts - eugh what are all those useless semicolons they don't do anything what's the point of them etc.

One important point is that it allows you to rearrange the whitespace in your code, without changing the execution meaning of your code. Which is pretty useful in making your code beautiful and readable and avoiding bugs.

[ Parent | on HN ]

Re:Semicolons in JavaScript are optional by danh on Friday June 25, 2010 @04:44AM (#1460321)

I don't think semicolons help your example.

    return
    {
        foo: 7
    };

still returns undefined.

[ Parent | on HN ]

Re:Semicolons in JavaScript are optional by axod on Friday June 25, 2010 @04:46AM (#1460325)

And that's one of the reasons (IMHO) that bracketing style sucks.

I was really explaining why rookies will make mistakes with js. The simplest way to prevent those types of errors is to always use ; and to use { on the same line style.

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Re:Semicolons in JavaScript are optional by kls on Friday June 25, 2010 @08:27AM (#1460547)

I understand the curly on the same line thing can bite you in Javascript, but man I find it so much easier to read when I can match them up by line of sight on a new line, that is one of my big pet peeves.

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Re:Semicolons in JavaScript are optional by troels on Friday June 25, 2010 @07:31AM (#1460469)

> It's looks cleaner, and ...

I think my new pet-peeve is the word "clean". What you mean, when you say that, is that it looks good, according to your taste. That's a rather subjective statement, disguised as an objective one.

(end of rant)

[ Parent | on HN ]

Re:Semicolons in JavaScript are optional by axod on Friday June 25, 2010 @07:40AM (#1460481)

Yeah point taken. I guess what I mean here is that it removes ambiguity and separates logic (What the code is going to do) from display (How I like my source code laid out).

I wasn't suggesting that languages that don't have semicolons look ugly or unclean. I do a lot of assembly language but obviously there is no real issue there with semicolon/line endings, since the convention is to write a single instruction per line.

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Re:Semicolons in JavaScript are optional by peti on Friday June 25, 2010 @04:37AM (#1460312)

The original argument is not about the minifier, but about semicolons. By the way, why would your better minifier introduce a semicolon here ? This is obviously a useless character in this example.

Also, I don't understand how adding a semicolon could help against the "stupid error" you cite. Could anyone please explain ?

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Re:Semicolons in JavaScript are optional by axod on Friday June 25, 2010 @04:45AM (#1460322)

I don't actually remember what closure advanced mode does. It's quite possible it does remove ";" in some instances. But really, you either need a newline or a ";" to mark the end of a statement, so the question is fairly moot - it's gonna be 1 byte either way.

If you always put semicolons to mark the end of a statement, then seeing a statement without one would be like seeing a megablocks brick in your lego box - glaringly obvious and extremely offensive.

IMHO that backeting style sucks, and shouldn't be used, at least in js.

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Re:Semicolons in JavaScript are optional by peti on Friday June 25, 2010 @05:09AM (#1460346)

If you write one statement per line, the code is very clear, and there is no need for semicolons. It is after all possible, according to the syntax, and a minifier should be able to understand it, as well as your browser.

I am certainly not against coding practices or readability. With (Q)BASIC, you could also add semicolons and have multiple statements per line, but who did ? It seems that it is the same with Javascript, semicolons are separators between statements, as well as newlines : why write both ? just to be sure they are well separated ?

[ Parent | on HN ]

Re:Semicolons in JavaScript are optional by axod on Friday June 25, 2010 @06:41AM (#1460415)

it may be 'clear' to you, but as has been pointed out, it can be ambiguous as to what the code will do. The example with a line starting with an open bracket is one such example.

Why force yourself to remember edge cases, when you can just remove that whole class of bugs by being explicit about what you mean...

[ Parent | on HN ]