The WorkerGlobalScope interface of the Web Workers API is an interface representing the scope of any worker. Workers have no browsing context; this scope contains the information usually conveyed by Window objects — in this case event handlers, the console or the associated WorkerNavigator object. Each WorkerGlobalScope has its own event loop.
The dump() method of the WorkerGlobalScope interface allows you to write a message to stdout — i.e. in your terminal, in Firefox only. This is the same as Firefox's window.dump, but for workers.
The close() method of the WorkerGlobalScope interface discards any tasks queued in the WorkerGlobalScope's event loop, effectively closing this particular scope.
The importScripts() method of the WorkerGlobalScope interface synchronously imports one or more scripts into the worker's scope.
The location read-only property of the WorkerGlobalScope interface returns the WorkerLocation associated with the worker. It is a specific location object, mostly a subset of the Location for browsing scopes, but adapted to workers.
The navigator read-only property of the WorkerGlobalScope interface returns the WorkerNavigator associated with the worker. It is a specific navigator object, mostly a subset of the Navigator for browsing scopes, but adapted to workers.
The onclose property of the WorkerGlobalScope interface represents an EventHandler to be called when the close event occurs and bubbles through the Worker.
The onerror property of the WorkerGlobalScope interface represents an EventHandler to be called when the error event occurs and bubbles through the Worker.
The onlanguagechange property of the WorkerGlobalScope interface represents an EventHandler to be called when the languagechange event occurs and bubbles through the Worker.
The onoffline property of the WorkerGlobalScope interface represents an EventHandler to be called when the offline event occurs and bubbles through the Worker.
The ononline property of the WorkerGlobalScope interface represents an EventHandler to be called when the online event occurs and bubbles through the Worker.
The  performance read-only property of the WorkerGlobalScope interface returns a Performance object to be used on the worker.
The self read-only property of the WorkerGlobalScope interface returns a reference to the WorkerGlobalScope itself. Most of the time it is a specific scope like DedicatedWorkerGlobalScopeSharedWorkerGlobalScope, or ServiceWorkerGlobalScope.