class Person{  constructor(name,age) {    this.name = name    this.age = age  }    running(){    console.log("yep,i am running")  }}
class Student extends Person{  constructor(name,age,sno) {    super(name,age);    this.sno = sno  }}

var Person = /*#__PURE__*/function () {  function Person(name, age) {    _classCallCheck(this, Person);
    this.name = name;    this.age = age;  }
  _createClass(Person, [{    key: "running",    value: function running() {      console.log("yep,i am running");    }  }]);
  return Person;}();
var Student = /*#__PURE__*/function (_Person) {  _inherits(Student, _Person);
  var _super = _createSuper(Student);
  function Student(name, age, sno) {    var _this;
    _classCallCheck(this, Student);
    _this = _super.call(this, name, age); // 通过 call 绑定 this     _this.sno = sno;    return _this;  }
  return Student;}(Person);

this.name = namethis.age = agethis.sno = sno

// Full spec-compliant TodoMVC with localStorage persistence// and hash-based routing in ~120 effective lines of JavaScript.
// localStorage persistenceconst STORAGE_KEY = "todos-vuejs-2.0";const todoStorage = {  fetch() {    const todos = JSON.parse(localStorage.getItem(STORAGE_KEY) || "[]");    todos.forEach((todo, index) => {      todo.id = index;    });    todoStorage.uid = todos.length;    return todos;  },  save(todos) {    localStorage.setItem(STORAGE_KEY, JSON.stringify(todos));  },};
// visibility filtersconst filters = {  all(todos) {    return todos;  },  active(todos) {    return todos.filter((todo) => !todo.completed);  },  completed(todos) {    return todos.filter((todo) => todo.completed);  },};
// app Vue instanceconst app = Vue.createApp({  // app initial state  data() {    return {      todos: todoStorage.fetch(),      newTodo: "",      editedTodo: null,      visibility: "all",    };  },
  // watch todos change for localStorage persistence  watch: {    todos: {      handler(todos) {        todoStorage.save(todos);      },      deep: true,    },  },
  // computed properties  // http://vuejs.org/guide/computed.html  computed: {    filteredTodos() {      return filters[this.visibility](this.todos);    },    remaining() {      return filters.active(this.todos).length;    },    allDone: {      get() {        return this.remaining === 0;      },      set(value) {        this.todos.forEach((todo) => {          todo.completed = value;        });      },    },  },
  // methods that implement data logic.  // note there's no DOM manipulation here at all.  methods: {    pluralize(n) {      return n === 1 ? "item" : "items";    },    addTodo() {      var value = this.newTodo && this.newTodo.trim();      if (!value) {        return;      }      this.todos.push({        id: todoStorage.uid++,        title: value,        completed: false,      });      this.newTodo = "";    },
    removeTodo(todo) {      this.todos.splice(this.todos.indexOf(todo), 1);    },
    editTodo(todo) {      this.beforeEditCache = todo.title;      this.editedTodo = todo;    },
    doneEdit(todo) {      if (!this.editedTodo) {        return;      }      this.editedTodo = null;      todo.title = todo.title.trim();      if (!todo.title) {        this.removeTodo(todo);      }    },
    cancelEdit(todo) {      this.editedTodo = null;      todo.title = this.beforeEditCache;    },
    removeCompleted() {      this.todos = filters.active(this.todos);    },  },
  // a custom directive to wait for the DOM to be updated  // before focusing on the input field.  // http://vuejs.org/guide/custom-directive.html  directives: {    "todo-focus": {      updated(el, binding) {        if (binding.value) {          el.focus();        }      },    },  },});
// mountconst vm = app.mount(".todoapp");
// handle routingfunction onHashChange() {  const visibility = window.location.hash.replace(/#\/?/, "");  if (filters[visibility]) {    vm.visibility = visibility;  } else {    window.location.hash = "";    vm.visibility = "all";  }}
window.addEventListener("hashchange", onHashChange);onHashChange();

this.state = {  message: "Hello World"}// ...this.setState({  message: "Hello React"})console.log(this.state.message) // Hello World

this.setState({  message: "Hello React"},() => {  console.log(this.state.message) // Hello React})

componentDidUpdate() {  console.log(this.state.message) // Hello React}

changeText() {  setTimeout(() => {    this.setState({      message: "你好呀，李银河"    })    console.log(this.state.message) // 你好呀，李银河  }, 0)}

componentDidMount() {  const btnEl = document.getElementById("btn")  btnEl.addEventListener('click',() => {    this.setState({      message: "你好呀，李银河"    })    console.log(this.state.message) // 你好呀，李银河  })}

// Object.assign({},prevState,partialState)Object.assign({},this.state,{message: "你好呀，李银河"})

shouldComponentUpdate(newProps, newState) {  // 修改相同引用类型（Array）数据并不会走下行逻辑  if(newState.books !== this.state.books){    return true   }  return false}

console.log(variate);let variate = 10;

console.log(variate); // undefinedvar variate = 10;

var variate;console.log(variate); // undefinedvariate = 10;