Light Table, which I presume to be defunct, comes to mind. (http://lighttable.com/#features http://lighttable.com/#features) But if you're willing to do withou

Light Table, which I presume to be defunct, comes to mind. (http://lighttable.com/#features http://lighttable.com/#features) But if you're willing to do without the "as you edit" requirement, then what you're left with is a plain old breakpoint debugger. Certainly, there are many IDEs that have those builtin.