JS设计模式之状态模式概念与用法分析

function Context( _state ) {
 this.state = _state;
 this.request = function() {
  this.state.Handle( this );
 }
}
function ConcreteStateA() {
 this.Handle = function( context ) {
  console.log("A");
  context.state = new ConcreteStateB();
 }
}
function ConcreteStateB() {
 this.Handle = function( context ) {
  console.log("B");
  context.state = new ConcreteStateA();
 }
}
// 设置Context的初始状态为ConcreteStateA
var context = new Context(new ConcreteStateA());
// 不断地进行请求，更改状态
context.request();
context.request();