如何将两个JavaScript语句合并为一个

Question

Sometimes I want to combine two statements into one to omit curly braces in conditionals. For example, in PHP, instead of writing

if ($direction == 'south-east') {
    $x++;
    $y++;
    }

I would write

if ($direction == 'south-east') $x++ and $y++;

but is there a way to do that in JavaScript? Writing x++ && y++ doesn't seem to work.

Answer 1

Curly braces aren't that bad, but - in very specific cases - you can enhance your code by using commas :

if (direction == 'south-east') x++, y++;

Here's the fiddle: http://jsfiddle.net/FY4Ld/

Answer 2

You can do it like this:

var x = 0,
    y = 0,
    cond = true;

if (cond) ++x && ++y;

Note: This doesn't work if x is -1 ;

Or without if :

cond && ++x && ++y;

---

So your code would look like this:

if ($direction == 'south-east') $x++ && $y++;

Note that the ++ operators is after the variable that means this won't work if $x is 0 .

++x returns falsy if x is -1
x++ returns falsy if x is 0

Answer 3

{ } that you use does just that - combines statements in one block usable with any flow control statement. You can place entire block on one line - JS doesn't care about whitespace in this case.