`if` statements – one line vs. one expression

[tomek-he-him]

Until I started using ESLint with your configuration I saw nothing against the rules in this:

$ cat if.js
const [one, two] = [1, 2];

if (one !== two) throw new Error(
  'One does not equal two'
);

But ESLint does:

$ eslint if.js 

if.js
  3:0  error  Expected { after 'if' condition  curly

✖ 1 problem (1 error, 0 warnings)

Is this intended? In my opinion the pattern I’ve been using is explicit – and more readable than this:

if (one !== two) {
  throw new Error(
    'One does not equal two'
  );
}

The parens form a visual brace-like block much like in #438.

[ljharb]

Our rules seem to require either:

if (one !== two) throw new Error('One does not equal two');

or, as an alternative to your last example:

if (one !== two) {
  throw new Error('One does not equal two');
}

[tomek-he-him]

Yeah, both of your examples look good with a five-word error message. I use my variant because my error messages tend to get long and descriptive – much like in the #438 example.

So it’s a question of:

if (one !== two) throw new Error(
  'One does not equal two. This error is common when you try to determine if ' +
  'the number `1` has the same value as the number `2`. Please try again, or ' +
  '– if that fails – get in touch with your administrator.'
);

vs.

if (one !== two) throw new Error('One does not equal two. This error is common when you try to determine if the number `1` has the same value as the number `2`. Please try again, or – if that fails – get in touch with your administrator.');

vs.

if (one !== two) {
  throw new Error(
    'One does not equal two. This error is common when you try to determine ' +
    'if the number `1` has the same value as the number `2`. Please try ' +
    'again, or – if that fails – get in touch with your administrator.'
  );
}

The second is obviously invalid. And I do prefer the first to the last – for the sake of readability.

But feel free to close the issue if you don’t think my point makes sense – I’ll adapt.

[tomek-he-him]

Just one more thought to support my suggestion.

<a>(<b>, <c>);

is semantically the same thing as:

<a>(
  <b>,
  <c>
);

– you just use one or the other depending on the length of the <a>, <b>, <c> expressions. When maintaining code you often switch between the first and second form.

It matters to me whether a chunk of code is one expression or statement, not whether it fits in one line.

Therefore, these should also be equivalent in any case:

throw new Error('One does not equal two');

throw new Error(
  'One does not equal two'
);

– whether they stand freely, after an if statement, or anywhere else there’s place for one statement.

[goatslacker]

If we go with this for #438 then we should apply the same rule for if statements.

Our rule makes the distinction that if it fits on one line then it's good to omit braces, otherwise we add the braces.

[ljharb]

@englishextra your comment is both unhelpful and condescending; I'm going to delete it. Please be respectful in the future.