jQuery assertion support / defensive programming?

Question

Is there any built in support in jQuery for basic assertion checking, primarily of things like \'expected number of returned elements\'.

For instance I may have a simple

Answer 1

I created a plugin for that: jquery-assert. You could use it like this:

Make sure, one or more elements were found, before calling the next function:

$('#element01').assertFound().val('x')

Assert that 1 element was selected:

$('#element01').assertOne(); // same as assertFound(1)

Make sure a given number of elements were found before calling further functions:

$('.item').assertFound(10).find('p').assertFound(10).data(...)