V-brake noodle broken: replace immediately? With what?
A noodle is totally cheap, and you should replace this immediately even if the brake appears to be working.   Dragging the inner around a sharp bend will fray the strands, leading to a sudden failure and a lack of front brake when it snaps.

Noodles come in two different bend radius.


90 degrees, often used on the rear brake
135 degrees, which is most common on the front brake.


Your folding bike might use either, it looks like a 90 degree one to me.

Note, you should change the inner brake cable at the same time.  Depending on condition, its also a good time to replace the outer if anything is wrong with it, like cracks or bends or rust.