JavaScript设计模式：代理模式原理与实例解析

var Shape = function(color){
  console.log('创建了一个对象');
  this.color = color;
  this.x;
  this.y;
  this.radius;
 
  this.setAttr = function(x, y, radius){
    this.x = x;
    this.y = y;
    this.radius = radius;
  }
  this.drawCircle = function(){
    console.log('画圆： 颜色：' + this.color + ' x:' + this.x + ' y:' + this.y + ' radius:' + this.radius)
  }
  this.drawSquare = function(){
    console.log('画方： 颜色：' + this.color + ' x:' + this.x + ' y:' + this.y )
  }
  this.drawTriangle = function(){
    console.log('画三角： 颜色：' + this.color + ' x:' + this.x + ' y:' + this.y )
  }
}
 
var proxyShape = function(color, x, y, radius){
  this.color = color;
  this.x = x;
  this.y = y;
  this.radius = radius;
  this.shape = null;
  this.drawSquare = function(){
    if(this.shape === null){
      this.shape = new Shape(this.color);
      this.shape.setAttr(this.x, this.y, this.radius);
    }
    this.shape.drawSquare();
  }
}
 
var square = new proxyShape('red', 10, 10);
square.drawSquare();
square.drawSquare();
// 创建了一个对象
// 画方： 颜色：red x:10 y:10
// 画方： 颜色：red x:10 y:10