Question

I have a webservice (RestEasy) returning a JSON object containing a List<..> element. I am trying to parse the results in a Javascript for loop. If the List<> element has 2 or more elements, all is well. If the List<> element has only one element, the Javascript loop breaks.

This is because the JSON respresentation actually changes when there is only one element. For example:

{"parent":[{"a":1},{"b":2}]}

works just fine … but for some reason, the JSON looks like this for one child:

{"parent":{"a":1}}

Note … that the array indicator [] is missing.

Is that standard JSON? This type of notation forces ugly, unnecessary checks in my javascript for existence or size, etc of an expected array …

Is this consistent standard practice? Why doesn’t JSON return a list of one?

{"parent":[{"a":1}]}

Is this possibly an artifact of my server side and would other server side generators actually build a different JSON representation? I even tried to use dojo.forEach and it works great until it reaches the single element array that unfortunalty, lacks any type of list notation.

Answer 1

This is an artifact of your server side. Might be your framework supplies the datastructure to the JSON generator in this way, I guess it’s not the problem of the generator itself.