Fix: memento state access

src/Memento/Book/index.ts

@@ -1,65 +1,64 @@
 export interface Memento {
-  getName(): string;
-  getSnapshotDate(): Date;
-  getText(): string;
+    getName(): string;
+    getSnapshotDate(): Date;
 }
 
 class Editor {
-  private text: string;
+    private text: string;
 
-  constructor(private name: string) {
-    this.text = "";
-  }
+    constructor(private name: string) {
+        this.text = '';
+    }
 
-  makeSnapshot(): Memento {
-    return new Snapshot(this.name, this.text);
-  }
+    makeSnapshot(): Memento {
+        return new Snapshot(this.name, this.text);
+    }
 
-  restore(memento: Memento) {
-    this.text = memento.getText();
-  }
+    restore(memento: Memento) {
+        this.text = (memento as Snapshot).getText();
+    }
 
-  editText(newText: string) {
-    this.text = newText;
-  }
+    editText(newText: string) {
+        this.text = newText;
+    }
 
-  displayText() {
-    console.log("Current Text: " + this.text);
-  }
+    displayText() {
+        console.log(`Current Text: ${this.text}`);
+    }
 }
 
 class Snapshot implements Memento {
-  private name: string;
-  private text: string;
-  private date: Date;
-
-  constructor(name: string, text: string) {
-    this.name = name;
-    this.text = text;
-    this.date = new Date();
-  }
-
-  getName(): string {
-    return this.name;
-  }
-
-  getSnapshotDate(): Date {
-    return this.date;
-  }
-
-  getText(): string {
-    return this.text;
-  }
+    private name: string;
+    private text: string;
+    private date: Date;
+
+    constructor(name: string, text: string) {
+        this.name = name;
+        this.text = text;
+        this.date = new Date();
+    }
+
+    getName(): string {
+        return this.name;
+    }
+
+    getSnapshotDate(): Date {
+        return this.date;
+    }
+
+    getText(): string {
+        return this.text;
+    }
 }
 
-const editor = new Editor("Document 1");
+const editor = new Editor('Document 1');
 
-editor.editText("This is the initial text");
+editor.editText('This is the initial text');
 editor.displayText();
 
 const snapshot1 = editor.makeSnapshot();
 
-editor.editText("Text after editing");
+editor.editText('Text after editing');
 editor.displayText();
 
 editor.restore(snapshot1);

src/Memento/Conceptual/index.ts

@@ -73,7 +73,7 @@ class Originator {
      * RU: Восстанавливает состояние Создателя из объекта снимка.
      */
     public restore(memento: Memento): void {
-        this.state = memento.getState();
+        this.state = (memento as ConcreteMemento).getState();
         console.log(`Originator: My state has changed to: ${this.state}`);
     }
 }
@@ -87,10 +87,7 @@ class Originator {
  * как дата создания или название. Однако он не раскрывает состояние Создателя.
  */
 interface Memento {
-    getState(): string;
-
     getName(): string;
-
     getDate(): string;
 }
 
@@ -103,7 +100,6 @@ interface Memento {
  */
 class ConcreteMemento implements Memento {
     private state: string;
-
     private date: string;
 
     constructor(state: string) {

src/Memento/RealWorld/index.ts

@@ -8,7 +8,11 @@
  */
 const DEFAULT_MONTHLY_EXPENSES_LIMIT = 0;
 
-class EmployeeOriginator {
+interface Originator {
+    saveSnapshot: () => Memento;
+}
+
+class EmployeeOriginator implements Originator {
     private _name: string;
     private _salary: number;
     private _monthlyExpensesLimit: number;
@@ -33,17 +37,17 @@ class EmployeeOriginator {
         this._monthlyExpensesLimit = newLimit;
     }
 
-    public saveSnapshot(): Memento<EmployeeState> {
-        return new EmployeeMemento({
+    public saveSnapshot(): Memento {
+        return new EmployeeMemento(this,{
             salary: this._salary,
             monthlyExpensesLimit: this._monthlyExpensesLimit,
         });
     }
 
-    public restore(memento: Memento<EmployeeState>): void {
-        this._salary = memento.state.salary;
-        this._monthlyExpensesLimit = memento.state.monthlyExpensesLimit;
-        console.log(`Originator: Restored state from memento: ${memento.name}`);
+    public setState(mementoName: string, state: EmployeeState): void {
+        this._salary = state.salary;
+        this._monthlyExpensesLimit = state.monthlyExpensesLimit;
+        console.log(`Originator: Restored state from memento: ${mementoName}`);
     }
 
     public showState(): void {
@@ -58,10 +62,10 @@ class EmployeeOriginator {
  * monthlyExpensesLimit in the memento constructor and moving the restore
  * method to the memento class instead of the originator
  */
-interface Memento<T> {
-    readonly state: T;
+interface Memento {
     readonly name: string;
     readonly date: Date;
+    readonly restore: () => void;
 }
 
 /**
@@ -73,12 +77,14 @@ interface EmployeeState {
     monthlyExpensesLimit: number;
 }
 
-class EmployeeMemento implements Memento<EmployeeState> {
+class EmployeeMemento implements Memento {
     private _state: EmployeeState;
     private _date: Date;
     private _name: string;
+    private _originator: EmployeeOriginator;
 
-    constructor(state: EmployeeState) {
+    constructor(originator: EmployeeOriginator, state: EmployeeState) {
+        this._originator = originator;
         this._state = state;
         this._date = new Date();
         this._name = `date=${this._date.toISOString().substring(0, 10)}, \
@@ -89,14 +95,17 @@ ${this._state.monthlyExpensesLimit}`;
     get state() { return this._state; }
     get name() { return this._name; }
     get date() { return this._date; }
+
+    public restore(): void {
+        this._originator.setState(this._name, this._state);
+    }
 }
 
 /**
  * EN: The Caretaker doesn't need to access the state of the originator.
  */
 class EmployeeCaretaker {
-    private _employeeMementos: Memento<EmployeeState>[] = [];
-
+    private _employeeMementos: Memento[] = [];
     private _employee: EmployeeOriginator;
 
     constructor(employee: EmployeeOriginator) {
@@ -115,7 +124,7 @@ class EmployeeCaretaker {
         const employeeMementoToRestore = this._employeeMementos.pop();
 
         console.log(`Employee caretaker: Restoring memento: ${employeeMementoToRestore.name}`);
-        this._employee.restore(employeeMementoToRestore);
+        employeeMementoToRestore.restore();
     }
 
     public showHistory(): void {