This directory contains examples of the Memento design pattern implemented in TypeScript. Memento is a behavioral design pattern that enables the preservation and retrieval of an object's previous state, allowing for undo and redo functionalities. This pattern promotes encapsulation by ensuring that the object's internal details remain hidden during the process of state capture and restoration. If at any point you would like to obtain and run these files refer to the root README.md found here.
The conceptual example can be found in conceptual.ts and ran from conceptual.js. The TypeScript files contains the code and explanations of what each element does in the design pattern.
The real world example I chose to implement is a super simple text editor. The editor can save the 'file' and then undo changes to revert back to older saved versions. The TextFile class represents the originator and has our bussiness logic to write the the 'file', save the 'file' and restore older version. The Memento interface is implemented by the TextFileHistory that can return the state and other data. Lastly our caretaker is teh TextEditor class which holds the file history and can be used to get a list of previous version and save the file.