实现迭代器模式示例，添加任务结构体、迭代器接口及具体实现，增强代码可读性

ts/src/iterator/index.ts

@@ -0,0 +1,92 @@
+/*
+实例：
+汤宝宝有一张TODO表，记录着自己想干的事情。
+*/
+
+// 任务结构体 - 迭代器元素
+interface Todo {
+  content: string;
+  done: boolean;
+}
+
+// 迭代器接口
+interface IIterator {
+  First(): Todo;
+  Next(): Todo;
+  isDone(): boolean;
+  CurrentItem(): number;
+}
+
+// 具体迭代器 - 汤宝宝的TODO表迭代器
+
+class TodoListIterator implements IIterator {
+  todoList: TodoList;
+  current: number;
+  constructor(todoList: TodoList) {
+    this.todoList = todoList;
+    this.current = 0;
+  }
+  First(): Todo {
+    this.current = 0;
+    return this.todoList.todos[this.current];
+  }
+  Next(): Todo {
+    this.current += 1;
+    return this.todoList.todos[this.current];
+  }
+  isDone(): boolean {
+    return this.current >= this.todoList.todos.length;
+  }
+  CurrentItem(): number {
+    if (this.current < 0 || this.current >= this.todoList.todos.length) {
+      return this.todoList.todos.length;
+    }
+    return this.current + 1;
+  }
+}
+
+// 集合接口
+interface ICollection {
+  createIterator(): IIterator;
+}
+
+// 具体集合 - 汤宝宝的TODO表
+class TodoList implements ICollection {
+  todos: Todo[];
+  constructor(todos: Todo[]) {
+    this.todos = todos;
+  }
+
+  createIterator(): IIterator {
+    return new TodoListIterator(this);
+  }
+}
+
+(function () {
+  console.log("============= 迭代器模式 =============");
+
+  // 创建TODO表并添加任务
+  const todoList = new TodoList([
+    { content: "学习Go语言", done: true },
+    { content: "完成设计模式作业", done: false },
+    { content: "锻炼身体", done: false },
+  ]);
+
+  // 创建迭代器
+  const iterator = todoList.createIterator();
+
+  // 使用迭代器遍历TODO表
+  for (
+    let item = iterator.First();
+    !iterator.isDone();
+    item = iterator.Next()
+  ) {
+    console.log(
+      `当前第 ${iterator.CurrentItem()} 项任务内容: ${
+        item ? item.content : ""
+      } 是否完成: ${item && item.done ? "已完成" : "未完成"}`
+    );
+  }
+
+  console.log("\n=========== 迭代器模式结束 ===========");
+})();