While they share the same name, and are both reactive primitives, there are some fairly key differences between these signals and the QT signals and slots mechanism.
The main one is that QT signals are, as far as I understand, a fairly static construct - as you construct the various components of the application, you also construct the reactive graph. This graph might be updated over time, but usually when components are mounted and unmounted. JS signals, however, are built fresh every time they are executed, which makes them much more dynamic.
In addition, dependencies in JS signals are automatic rather than needing to be explicitly defined. There's no need to call a function like connect, addEventListener, or subscribe, you just call the original signal within the context of a computation, and the computation will subscribe to that signal.
Thirdly, in JS signals, you don't necessarily need to have a signal object to be able to subscribe to that signal. You can build an abstraction that doesn't necessarily expose the signal value itself, and instead provides getter functions that may call the underlying signal getter. And this same abstraction can be used both inside and outside of other reactive computations.
So on the one hand, yes, JS signals are just another reactivity tool and therefore will share features with many existing tools like signals and slots, observables, event emitters, and so on. But within that space, they are also a meaningful difference in how that reactivity occurs and is used.
The main one is that QT signals are, as far as I understand, a fairly static construct - as you construct the various components of the application, you also construct the reactive graph. This graph might be updated over time, but usually when components are mounted and unmounted. JS signals, however, are built fresh every time they are executed, which makes them much more dynamic.
In addition, dependencies in JS signals are automatic rather than needing to be explicitly defined. There's no need to call a function like connect, addEventListener, or subscribe, you just call the original signal within the context of a computation, and the computation will subscribe to that signal.
Thirdly, in JS signals, you don't necessarily need to have a signal object to be able to subscribe to that signal. You can build an abstraction that doesn't necessarily expose the signal value itself, and instead provides getter functions that may call the underlying signal getter. And this same abstraction can be used both inside and outside of other reactive computations.
So on the one hand, yes, JS signals are just another reactivity tool and therefore will share features with many existing tools like signals and slots, observables, event emitters, and so on. But within that space, they are also a meaningful difference in how that reactivity occurs and is used.