ES5/ES6的继承的区别

class声明会提升，但是不会被初始化赋值，所以优先初始化赋值，则会进入暂时性死区，类似let，const变量

const bar = new Bar(); // ok
function Bar() {
    this.bar = 42;
}

const foo = new Foo() // Foo is not defined
class Foo{
  constructor() {
    this.foo = 42;
  }
}

class内部启动 严格模式

function Bar(){
    baz = 42; // OK
}
const bar = new Bar();

class Foo {
    constructor() {
        foo = 42; // foo is not defined
    }
}
const foo = new Foo();

class的所有方法（包括静态方法和示例方法）都没有原型对象portotype，所以也没有[[construct]]，不能使用new来调用

function Bar() {
   this.bar = 42;
}

Bar.prototype.print = function (){
    console.log(this.bar)
}
const bar = new Bar();
cont barPrint = new bar.print() ; // 42

class Foo {
    constructor() {
        this.foo = 42;
    }
    print () {
        console.log(this.foo)
    }
}

const foo = new Foo();
const fooPrint = new foo.print(); // foo.print is not a constructor

必须使用new来调用class

function Bar() {
    this.bar = 42;
}

const bar = Bar() ; // bar.bar: 42

class Foo() {
    constructor () {
        this.foo = 42;
    }
}

const foo = Foo() // Class constructor Foo cannot be invoked widhout 'new'

class内部无法重写类名

function Bar() {
    Bar = 'Baz' ; 
    this.bar = 42;
}
const bar = new Bar();
Bar // 'Baz'
bar.bar // 42

class Foo{
    constructor() {
        this.foo = 12;
        Foo = 'Fol' ; // err:Assignment to constant variable
    }
}

const foo = new Foo();
Foo = 'Fol'; //