const object_to_watch = obj; // Change to the object you are inspecting
const property_to_watch = 'example'; // Change to the property name in the object you are inspecting (here obj.example)

// Store the original value
object_to_watch.__storedValue = object_to_watch[property_to_watch];

Object.defineProperty(object_to_watch, property_to_watch, {
    get() {
        return this.__storedValue;
    },
    set(newValue) {
        // Break when setting the value
        // It can be useful to wrap this statement in a if () { } to check for specific values being set.
        debugger;
        this.__storedValue = newValue;
    }
});