As you scale your applications with more features, it becomes mandatory to understand how and when the MobX reactive system is being used. MobX comes with a set of debugging utilities that help you monitor and trace the various activities happening inside it. These give you a real-time view of all the observable changes, actions, and reactions firing inside the system.
Earlier, we saw the observe() function, which allows you to "observe" the changes happening to a single observable. But what if you wanted to observe changes happening across all observables without having to individually set up the observe() handlers? That is where spy() comes in. It gives you insight into how the various observables in your system are changing over time:
disposer = spy(listener: (event) => { })
It takes in a listener function that receives an event object carrying all the details. The event has properties very similar to the observe() handler. There...