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Memento

Memento is a behavioral pattern that lets you save and restore the previous state of an object without revealing the details of its implementation. It externalizes an object's internal state into a Memento object — a snapshot — that can be stored and later used to roll back the originator to that exact state. Classic use case: Ctrl+Z undo in any editor.

ℹ️Core idea: capture an object's internal state in a Memento without violating encapsulation, then restore that state later. The Originator creates and restores mementos; the Caretaker stores them but never inspects their contents.
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