Throw something when widget is actually not initialized

[homm]

For now uploadcare.Widget(".class") always successful, even if .class doesn't exist or there are many .class tags on the pages. An error should be thrown in the first case and warning in the second.

[ZNick1982]

I found several widget initialisators in the code: ns.Widget, ns.SingleWidget, ns.MultipleWidget
Should I add this check only for ns.Widget or I should modify other methods to?

[homm]

They are all use initializeWidget internal.

[ZNick1982]

Yes I saw it, Ok, I will update initializeWidget method

[homm]

Yes, please.

The difference between ns.Widget and ns.[Single/Multiple]Widget is the first doesn't check the type of the widget while the second does. This can be important when you want to be sure that the widget is single or multiple because they have different API.

[ZNick1982]

Done with pr: #310