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interface Todo {
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  id: number
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  name: string
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  done: boolean
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}
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const todo: Todo = {
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  done: false,
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  id: 0,
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  name: 'task',
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}
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interface StorageStrategy {
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  get(id: number): Todo
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  getAll(): Todo[]
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  delete(id: number): void
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  save(todo: Todo): void
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}
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type InitializerStrategy = (todo: Todo) => Todo
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class TodoDB {
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  constructor(
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    private readonly storage: StorageStrategy,
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    private readonly intializer: InitializerStrategy
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  ) {}
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  getItems(): Todo[] {
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    return this.storage.getAll()
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  }
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  getItem(id: number): Todo {
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    return this.storage.get(id)
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  }
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  addItem(todo: Todo): void {
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    const item = this.intializer(todo)
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    this.storage.save(item)
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  }
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  removeItem(id: number): void {
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    this.storage.delete(id)
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  }
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  updateItem(todo: Todo): Todo {
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    this.storage.save(todo)
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    return todo
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  }
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  completeItem(id: number): Todo {
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    const todo = this.storage.get(id)
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    const updated = {
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      ...todo,
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      done: true,
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    }
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    this.storage.save(updated)
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    return updated
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  }
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  resetItem(id: number): Todo {
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    const todo = this.storage.get(id)
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    const updated = {
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      ...todo,
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      done: false,
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    }
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    this.storage.save(updated)
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    return updated
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  }
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}
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class ListStorageStrategy implements StorageStrategy {
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  private todos: Todo[] = []
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  getAll(): Todo[] {
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    return this.todos
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  }
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  get(id: number): Todo {
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    const item = this.todos[id]
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    if (!item) {
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      throw new Error('Item not found')
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    }
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    return item
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  }
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  save(todo: Todo): void {
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    this.todos[todo.id] = todo
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  }
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  delete(id: number): void {
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    delete this.todos[id]
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  }
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}
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class MapStorageStrategy implements StorageStrategy {
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  private todos: Map<number, Todo> = new Map()
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  getAll(): Todo[] {
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    return Array.from(this.todos.entries()).map((el) => el[1])
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  }
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  get(id: number): Todo {
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    const item = this.todos.get(id)
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    if (!item) {
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      throw new Error('Item not found')
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    }
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    return item
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  }
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  save(todo: Todo): void {
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    this.todos.set(todo.id, todo)
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  }
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  delete(id: number): void {
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    this.todos.delete(id)
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  }
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}
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const alwaysIncompleteInitializer: InitializerStrategy = (todo) => ({
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  ...todo,
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  done: false,
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})
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const randomIdInitializer: InitializerStrategy = (todo) => ({
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  ...todo,
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  id: Math.random(),
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})
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const listTodos = new TodoDB(
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  new ListStorageStrategy(),
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  alwaysIncompleteInitializer
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)
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const mapTodos = new TodoDB(new MapStorageStrategy(), randomIdInitializer)
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const item1: Todo = {
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  done: false,
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  id: 1,
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  name: 'thing',
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}
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const item2: Todo = {
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  done: true,
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  id: 2,
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  name: 'thing',
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}
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listTodos.addItem(item1)
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mapTodos.addItem(item1)
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listTodos.addItem(item2)
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mapTodos.addItem(item2)
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console.log(listTodos.getItems())
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console.log(mapTodos.getItems())
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console.log(listTodos)
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console.log(mapTodos)
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console.log(listTodos.getItem(1))
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console.log(mapTodos.getItem(1))