A weak map is a [=infra/map=] in which keys are held weakly -i.e. items are removed if the key object is garbaged collected, and presence -in the map does not prevent garbage collection. This acts as an alternative -to defining properties directly on the key objects. - -
Unlike the ECMAScript [=WeakMap=] type, a weak map can -participate in the full set of operations available for a Map. -
A WebDriver session has a browsing context group node -map, which is a weak map between a browsing context group +map, which is a weak map between a browsing context group and a node id map. -
A node id map is weak map between nodes and their +
A node id map is weak map between nodes and their corresponding WebDriver node id.
A WebDriver session has a navigable seen nodes map -which is a weak map between a [=navigable=] and a set. +which is a weak map between a [=navigable=] and a set.
To get a node given session, browsing context, and reference: