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Badacadabra
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Add Memento (ES5 + ES6 + CoffeeScript + TypeScript)
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‎doc/GoF/Behavioral/Memento/Memento.dia

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‎doc/GoF/Behavioral/Memento/Memento.png

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‎doc/GoF/Behavioral/Memento/README.md

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# Synopsis
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I found an interesting article on the Web and I would like to save it in my browser for later reading. For some reasons, I always use private browsing.
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# Problem
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With private browsing, history is not kept by the browser. Of course we can use back and forward buttons to navigate in the current history during the browsing session, but with this technique, it would not be possible to identify easily our favorite webpages. Furthermore, interesting webpages would not be there anymore if we close the browser and open it again.
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# Solution
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Here we have to use bookmarks to save interesting webpages and the Memento pattern allows us to simulate that behavior. Implementing this pattern requires:
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* A concrete "originator" (the browser) which is responsible for the action
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* A concrete "memento" (a bookmark) which keeps the link to the interesting webpage
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* A concrete "caretaker" (the bookmarks manager) which keeps a list of bookmarks

‎src/CoffeeScript/GoF/Behavioral/Memento/Memento.coffee

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# ==============================
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# ORIGINATOR
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# ==============================
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class Browser
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constructor: (@_currentPage) ->
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saveCurrentPage: ->
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new Bookmark(@_currentPage)
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getCurrentPage: ->
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@_currentPage
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setCurrentPage: (@_currentPage) ->
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# ==============================
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# MEMENTO
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# ==============================
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class Bookmark
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constructor: (webpage) ->
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@_webpage = webpage
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getPage: ->
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@_webpage
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# ==============================
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# CARETAKER
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# ==============================
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class BookmarksManager
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constructor: ->
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@_bookmarks = []
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addBookmark: (bookmark) ->
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@_bookmarks.push(bookmark)
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getBookmark: (index) ->
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@_bookmarks[index]
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# ==============================
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# CLIENT CODE
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# ==============================
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browser = new Browser "http://www.badacadabra.net"
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bookmark = browser.saveCurrentPage()
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bookmarksManager = new BookmarksManager
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bookmarksManager.addBookmark bookmark
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browser.setCurrentPage "https://www.google.com"
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browser.setCurrentPage "https://www.amazon.com"
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bookmark = browser.saveCurrentPage()
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bookmarksManager.addBookmark bookmark
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browser.setCurrentPage "https://www.twitter.com"
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console.log "Current page: #{browser.getCurrentPage()}"
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console.log "Latest bookmark: #{bookmark.getPage()}"
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console.log "First bookmark: #{bookmarksManager.getBookmark(0).getPage()}"

‎src/TypeScript/GoF/Behavioral/Memento/Memento.ts

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// ==============================
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// ORIGINATOR
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// ==============================
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class Browser {
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private currentPage: string;
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constructor(currentPage: string) {
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this.currentPage = currentPage;
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}
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public saveCurrentPage(): Bookmark {
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return new Bookmark(this.currentPage);
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}
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public getCurrentPage(): string {
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return this.currentPage;
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}
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public setCurrentPage(webpage: string): void {
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this.currentPage = webpage;
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}
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}
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// ==============================
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// MEMENTO
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// ==============================
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class Bookmark {
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private webpage: string;
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constructor(webpage: string) {
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this.webpage = webpage;
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}
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public getPage(): string {
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return this.webpage;
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}
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}
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// ==============================
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// CARETAKER
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// ==============================
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class BookmarksManager {
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private bookmarks: Bookmark[] = [];
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public addBookmark(bookmark: Bookmark): void {
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this.bookmarks.push(bookmark);
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}
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public getBookmark(index: number): Bookmark {
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return this.bookmarks[index];
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}
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}
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// ==============================
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// CLIENT CODE
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// ==============================
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let browser: Browser = new Browser("http://www.badacadabra.net"),
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bookmark: Bookmark = browser.saveCurrentPage(),
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bookmarksManager: BookmarksManager = new BookmarksManager();
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bookmarksManager.addBookmark(bookmark);
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browser.setCurrentPage("https://www.google.com");
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browser.setCurrentPage("https://www.amazon.com");
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bookmark = browser.saveCurrentPage();
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bookmarksManager.addBookmark(bookmark);
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browser.setCurrentPage("https://www.twitter.com");
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console.log("Current page: " + browser.getCurrentPage());
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console.log("Latest bookmark: " + bookmark.getPage());
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console.log("First bookmark: " + bookmarksManager.getBookmark(0).getPage());

‎src/Vanilla/GoF/Behavioral/Memento/Memento-ES5.js

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'use strict';
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// ==============================
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// ORIGINATOR
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// ==============================
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var Browser = (function() {
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function Browser(currentPage) {
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this._currentPage = currentPage;
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}
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Browser.prototype.saveCurrentPage = function () {
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return new Bookmark(this._currentPage);
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};
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Browser.prototype.getCurrentPage = function () {
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return this._currentPage;
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};
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Browser.prototype.setCurrentPage = function (webpage) {
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this._currentPage = webpage;
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};
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return Browser;
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})();
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// ==============================
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// MEMENTO
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// ==============================
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var Bookmark = (function () {
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function Bookmark(webpage) {
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this._webpage = webpage;
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}
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Bookmark.prototype.getPage = function () {
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return this._webpage;
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};
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return Bookmark;
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})();
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// ==============================
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// CARETAKER
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// ==============================
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var BookmarksManager = (function () {
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var bookmarks = [];
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function BookmarksManager() {}
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BookmarksManager.prototype.addBookmark = function (bookmark) {
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bookmarks.push(bookmark);
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};
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BookmarksManager.prototype.getBookmark = function (index) {
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return bookmarks[index];
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};
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return BookmarksManager;
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})();
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// ==============================
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// CLIENT CODE
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// ==============================
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var browser = new Browser("http://www.badacadabra.net"),
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bookmark = browser.saveCurrentPage(),
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bookmarksManager = new BookmarksManager();
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bookmarksManager.addBookmark(bookmark);
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browser.setCurrentPage("https://www.google.com");
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browser.setCurrentPage("https://www.amazon.com");
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bookmark = browser.saveCurrentPage();
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bookmarksManager.addBookmark(bookmark);
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browser.setCurrentPage("https://www.twitter.com");
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console.log("Current page: " + browser.getCurrentPage());
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console.log("Latest bookmark: " + bookmark.getPage());
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console.log("First bookmark: " + bookmarksManager.getBookmark(0).getPage());

‎src/Vanilla/GoF/Behavioral/Memento/Memento-ES6.js

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// ==============================
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// ORIGINATOR
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// ==============================
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class Browser {
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constructor(currentPage) {
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this._currentPage = currentPage;
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}
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saveCurrentPage() {
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return new Bookmark(this._currentPage);
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}
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getCurrentPage() {
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return this._currentPage;
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}
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setCurrentPage(webpage) {
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this._currentPage = webpage;
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}
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}
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// ==============================
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// MEMENTO
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// ==============================
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class Bookmark {
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constructor(webpage) {
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this._webpage = webpage;
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}
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getPage() {
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return this._webpage;
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}
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}
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// ==============================
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// CARETAKER
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// ==============================
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class BookmarksManager {
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constructor() {
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this._bookmarks = [];
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}
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addBookmark() {
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this._bookmarks.push(bookmark);
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}
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getBookmark(index) {
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return this._bookmarks[index];
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}
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}
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// ==============================
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// CLIENT CODE
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// ==============================
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let browser = new Browser("http://www.badacadabra.net"),
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bookmark = browser.saveCurrentPage(),
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bookmarksManager = new BookmarksManager();
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bookmarksManager.addBookmark(bookmark);
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browser.setCurrentPage("https://www.google.com");
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browser.setCurrentPage("https://www.amazon.com");
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bookmark = browser.saveCurrentPage();
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bookmarksManager.addBookmark(bookmark);
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browser.setCurrentPage("https://www.twitter.com");
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console.log("Current page: " + browser.getCurrentPage());
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console.log("Latest bookmark: " + bookmark.getPage());
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console.log("First bookmark: " + bookmarksManager.getBookmark(0).getPage());

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