broken hinge joint

is there a property to say if a hinge joint has been broken?

Basically I want to do

if(joint is broken){
do something;
}

if(!joint.connectedBody)
{
  ...
}

I don’t know if this works the way you want it to but the connected body variable is there.

No. When a joint breaks, it no longer exists. So the way to check for that is simply:

if (joint) {
....
}

If connectedBody doesn’t exist, the joint is attached to a point in space.