The AbstractWorker interface of the Web Workers API abstracts properties and methods common to all kind of workers, being Worker or SharedWorker.

AbstractWorker API Interface Reference Référence Web Workers

The AbstractWorker.onerror property of the AbstractWorker interface represents an EventHandler, that is a function to be called when the error event occurs and bubbles through the Worker.

AbstractWorker API EventHandler onerror Property Reference Référence Web Workers Workers