[Mapbender-dev] JSON revisited

Marc Jansen jansen.marc at gmx.de
Thu Jan 18 11:24:26 EST 2007

Christoph Baudson (WhereGroup) schrieb:
>>> Because JSON overloads several JS datatypes, some conflicts emerge. 
>>> For example, for (var attribute in object) suddenly doesn't work 
>>> anymore because it has an additional attribute: the JSON functions :-)
>> Is this the case? That's new to me... but the whole (actual) JSON 
>> coding is new to me ;-)
>> How often do we use
>> for ... in
>> though?
> The Json library adds function like "toJsonString" to data types like 
> Array. So if you have associative arrays you can't use the
> for (var x in y)
> anymore, because the function is part of the array. Well, there aren't 
> many situations where this construction is used in Mapbender, but 
> maybe this advice is helpful to someone someday.

You're totally right on this. One possible workaround would be the 

// is untested and could
// surely be rewritten...
var isFunction = function (testvar) {
  return (typeof(testvar) == 'function');

// your for ... in
for (var x in y)  {
  if (!isFunction(x)) {
    // this is certainly not a function

-- Marc

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