Question

As part of my unit tests (using QUnit) for a backbone project, I test some collection manipulation functions that return arrays of backbone models.

Is there a way to directly test (for sanity’s sake) whether the objects in my array extend Backbone.Model or should I just do a duck type check (and if so, how, and on which unique attribute, for example)?

Since there is no real “Class” construct in javascript, typeof obviously won’t do the trick here.

I could see this being useful in other tests down the road for my Collections, or to check that things are instances of my specific Backbone classes, etc.

Answer 1

How about using instanceof:

console.log(yourObject instanceof Backbone.Model);

The instanceof operator tests whether an object has in its prototype
chain the prototype property of a constructor.