JSOOP class

• 简单示例 

class Circle {
  constructor (radius) {
    this.radius = radius
    this.move = function() {}
  }
  draw() {
    console.log('draw')
  }
}

const c = new Circle(1)

 class本质是function，_classCallCheck用来确保使用了new

•  函数和表达式的区别

函数声明是置顶的，表达式不会置顶

sayHello()
sayHi()
function sayHello() {
  console.log('Hello')
}
const sayHi = function(){
  console.log('Hi')
}

 

 类表达式和类声明都不会置顶，

const c = new Circle()
class Circle {
}
const Square = class {}