Hey, just FYI, because these English rules about contractions can be very complex and confusing: you would never contract in this case. You would always write out “there is.” One helpful way to think about it is that “there is” is only contracted if it’s followed by an object:

• There’s a spider in the room!
• There’s the problem!

but if it’s followed by punctuation, don’t contract it:

• He thinks there isn’t, but there is.
• There is, and it is large.