listener-threw

[wizzard] a function passed to subscribe, select or watch threw. The change stands, and every other
listener still hears it. Fix that function, or catch inside it. …/errors/listener-threw

Printed with console.error by createWizard from @wizzard-packages/core, with what was thrown as the second argument, each time it throws on a change. The function is the listener, or for select also the selector or the equals it was given: both run on every change, before the listener is called. The selector’s first call, made by select() itself, throws to its caller and subscribes nothing.

A listener is called inside the write that changed the state, and a move writes more than once: it takes the lock, may mark a step as loading, and then lands or releases. A throw that escaped there would become the answer to the move - a next() that landed would reject, a cancel() the listener made would be lost - and the listeners after it would never hear the change, the binding’s own among them, leaving the screen behind the state. So the write is kept, every other listener still runs, and the one that threw stays subscribed: it runs again on the next change, and if the cause is still there it throws and prints this again. A listener whose promise rejects is reported the same way, when it rejects.

Read the error logged beside the message. Fix the function, or wrap its body in a try if what it calls is allowed to fail.