Trying to shorten a conditional statement in javascript

Question

What I want to do here is use the fewest bytes to call function f only if the variable a is not null. The function n shown will work fine, but according to my web browser, function m won't work. The browser states:

expected expression, got ';'

I then proceeded to take out the colon, figuring maybe that would do the trick, but I get the error "syntax error".

Is there a way I can shorten function n to a smaller size and have it still work or should I just stick with function n?

function g(){}
function f(){}

function m(){a?f()g():;}

function n(){if(a){f();g()}}

m will not work since f()g() is not valid...browser tells you why — epascarello, Dec 16 '15 at 04:31
My browser reports a syntax error at hte `g`, it doesn't even reach the one after the `:`. — Bergi, Dec 16 '15 at 04:31
What is the practical reason for that? Code must be readable, size is what minifiers + gzip were invented for? — zerkms, Dec 16 '15 at 04:34
I'm trying to compact my code because I have a lot of javascript and I want to make guests download fewer bytes. — Mike -- No longer here, Dec 16 '15 at 04:36
Are you trying to minify, by hand? There are a number of tools to do this more efficiently, and more quickly, for free... — Adam, Dec 16 '15 at 04:38
@Mike Do you realize their are resources that already do this for you? Did you try and see if it shrink it down for you? — epascarello, Dec 16 '15 at 04:39
@Mike: No reason to do that by hand. There's a variety of tools that has automated this. — Bergi, Dec 16 '15 at 04:41
If I rely on 3rd party tools to do all my code shrinking, then I'll be doing things their way and I'll be learning nothing. Additionally, their results might not work for older browsers. — Mike -- No longer here, Dec 16 '15 at 04:46
@Vohuman what if they are about to apply for a junior JS-minifier position? — zerkms, Dec 16 '15 at 04:57

Alexander O'Mara · Answer 1 · 2015-12-16T04:54:57.560

3

Code golfing?

Fore!

*ahem*

You could use && for the conditional, and + to call them both together.

function m(){a&&f()+g()}

Total bytes: 24

Note: If by chance f or g returns an object, any valueOf methods will be called, which could have side-effects, but in this context I think that's unlikely.

edited Dec 16 '15 at 04:54

answered Dec 16 '15 at 04:38

Alexander O'Mara

58,688
18
163
171

1

beats closure compiler by 2 – epascarello Dec 16 '15 at 04:46
If `f` or `g` return an object that implements a `valueOf` that has side effects then it would behave differently to `if (a) { f(); g(); }` – zerkms Dec 16 '15 at 04:52
@zerkms True, but in this context I'm doubtful they return anything. I'll make a note of it though. – Alexander O'Mara Dec 16 '15 at 04:53
I'm gonna try every answer and see what works for IE 7 too. – Mike -- No longer here Dec 16 '15 at 05:30

score 2 · Accepted Answer · edited May 23 '17 at 11:44

You can do some tricks with the comma operator:

function m(){a?(f(),g()):…}

and of course the conditional operator always needs a third operand, you cannot just omit it, but use any (short) value:

function m(){a?(f(),g()):0}

You can work around that restriction by using the short-circuit behaviour of the AND operator (see What is "x && foo()"?):

function m(){a&&(f(),g())}

But don't do that. It makes your code totally unreadable.

Should I just stick with function n?

Yes, definitely.

function m() {
    if (a) {
        f();
        g();
    }
}

If you want to minify that, use one of the established minifiers instead of hand-optimising it.

" It makes your code totally unreadable." It is supposed to be when you are manually compacting it. — epascarello, Dec 16 '15 at 04:40

Trying to shorten a conditional statement in javascript

2 Answers2

Total bytes: 24