empty arguments

[jimmyshoes]

Is it acceptable to leave arguments empty
for example

<script>

function showIt(a,b,c){
if(a) alert(a);
if(b) alert(b);
if(c) alert(c);
}

showIt(1,2,3);
showIt(1);
showIt(1,null,null);

</script>

is showIt(1); ok or should you always use showIt(1,null,null);

 

[feherke]

Hi

is showIt(1); ok or should you always use showIt(1,null,null);

It is Ok.

But note that your [tt]if[/tt] condition will be evaluated to false not only when the given argument misses, but also when the following values are passed : [tt]false[/tt], 0, '', [tt]null[/tt], [tt]NaN[/tt], [tt]undefined[/tt]. The proper [tt]if[/tt] condition should be [tt]a!=undefined[/tt].

However the proper way to do it is to check the argument count :

[b]function[/b] [COLOR=darkgoldenrod]showIt[/color][teal]([/teal]a[teal],[/teal]b[teal],[/teal]c[teal])[/teal]
[teal]{[/teal]
  [b]if[/b] [teal]([/teal]arguments[teal].[/teal]length[teal]>=[/teal][purple]1[/purple][teal])[/teal] [COLOR=darkgoldenrod]alert[/color][teal]([/teal]a[teal]);[/teal]
  [b]if[/b] [teal]([/teal]arguments[teal].[/teal]length[teal]>=[/teal][purple]2[/purple][teal])[/teal] [COLOR=darkgoldenrod]alert[/color][teal]([/teal]b[teal]);[/teal]
  [b]if[/b] [teal]([/teal]arguments[teal].[/teal]length[teal]>=[/teal][purple]3[/purple][teal])[/teal] [COLOR=darkgoldenrod]alert[/color][teal]([/teal]c[teal]);[/teal]
[teal]}[/teal]

But if you are checking the [tt]arguments.length[/tt], is simple to use a [tt]for[/tt] and a single [tt]if[/tt] instead of 3 [tt]if[/tt]s :

[b]function[/b] [COLOR=darkgoldenrod]showIt[/color][teal]([/teal]a[teal],[/teal]b[teal],[/teal]c[teal])[/teal]
[teal]{[/teal]
  [b]for[/b] [teal]([/teal][b]var[/b] i[teal]=[/teal][purple]0[/purple][teal],[/teal]l[teal]=[/teal]arguments[teal].[/teal]length[teal];[/teal]i[teal]<[/teal]l[teal];[/teal]i[teal]++)[/teal]
    [COLOR=darkgoldenrod]alert[/color][teal]([/teal]arguments[teal][[/teal]i[teal]]);[/teal]
[teal]}[/teal]

Note that in this case you can just remove the declaration of the formal arguments, if they are not needed for other operations inside the [tt]function[/tt].

Feherke.

http://free.rootshell.be/~feherke/