sessions.getWindowValue()

Retrieves a value previously stored by a call to sessions.setWindowValue.

You can retrieve a value from a window even over a close/restore cycle: meaning that if you set a value, then the user closes the window, then restores the window using the browser's "restore window" feature (for example, by pressing Control+Shift+N), then you will be able to retrieve the value from the restored window. Note, though, that a restored window does not get the same ID as the original, so the ID you pass into getWindowValue() will be different from the ID you passed into setWindowValue(), even though they both refer to the same window.

This is an asynchronous function that returns a Promise.