Is there a way to use a variable name which has a function assigned to it, for example, to get the actual width of an element?
var xvar = function(){ return $('#y').width()}
And use it as
console.log(xvar);
Instead of
console.log(xvar());
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1You can't call a function without calling a function, in general, though you might want to look at using property getter functions (in newer JavaScript interpreters only). edit see @pimvdb's answer :-)Pointy– Pointy2012-06-06 14:11:30 +00:00Commented Jun 6, 2012 at 14:11
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3 Answers
Not with variables, but it is possible with properties on objects. It's called a getter.
var obj = {
get xvar() { return $('#y').width(); }
};
Then you can use:
obj.xvar; // will run the above function
(Theoretically, a way to use a variable getter is when an object's properties reflect the variables. For example, the window object.)
11 Comments
gdoron
+1. If I'm not wrong, it's not fully cross browser supported.
Florian Margaine
Is that ES5/6? I've never heard of this. It's awesome though.
gdoron
@FlorianMargaine. goggle javascript getter.
pimvdb
@gdororn: Very true, good point. @ Florian Magazine: ES5 specs are here.
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As long as your function returns String or Number this could be an alternative for non-ES5 environments:
var xvar = new function(id){
this.toString =
this.valueOf = function(){
return $(id).width()};
}('#y');
Comments
If I not mistake it will work because xvar will store reference to result of immediately-invoked function:
var xvar = (function() { return $('#y').width(); })();
console.log(xvar);
But after it you can't use xvar() version.
2 Comments
pimvdb
This is basically equivalent to
var xvar = $('#y').width();. It won't run the function on access.
Erik Reppen
Yeah, that just assigns the return value in the first place. You wouldn't get an updated version of width with that.