JSOOP module（模块化）_radius.console.log(`Circle with radius ${_

可以利用模块隐藏部分实现

const _radius = new WeakMap()

class Circle {
  constructor(radius) {
    _radius.set(this, radius)
  }
  draw() {
    console.log(`Circle with radius ${_radius.get(this)}`)
  }
}
const c = new Circle(10)
console.log(_radius.get(c))// 暴露了
c.draw()

CommonJS

// index.js
const { Circle } = require('./circle')
const c = new Circle(10)
c.draw()

// circle.js
const _radius = new WeakMap()

class Circle {
  constructor(radius) {
    _radius.set(this, radius)
  }
  draw() {
    console.log(`Circle with radius ${_radius.get(this)}`)
  }
}
module.exports.Circle = Circle

ES6 Module

// index.js
import { Circle } from './circle.js'
const c = new Circle(10)
c.draw()

// circle.js
const _radius = new WeakMap()

export class Circle {
  constructor(radius) {
    _radius.set(this, radius)
  }
  draw() {
    console.log(`Circle with radius ${_radius.get(this)}`)
  }
}

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