中介者模式/Mediator Pattern

什么是中介者模式

中介者模式（Mediator Pattern）是用来降低多个对象和类之间的通信复杂性。这种模式提供了一个中介类，该类通常处理不同类之间的通信，并支持松耦合，使代码易于维护。中介者模式属于行为型模式。

面向对象例子：

 class Player{
     constructor(name, teamColor, playerDirector) {
         this.name = name;
         this.teamColor = teamColor;
         this.status = 'live';
         this.playerDirector = playerDirector;
         this.add();
     }

     win() {
         console.log('for self win action: ' + this.name);
     }

     lose() {
         console.log('for self lose action: ' + this.name);
     }

     add() {
         console.log('for self add action: ' + this.name);
         this.playerDirector.recieveMessage('add', this);
     }

     remove() {
         console.log('for self remove action: ' + this.name);
         this.playerDirector.recieveMessage('remove', this);
     }

     die() {
         console.log('for self die action: ' + this.name);
         this.playerDirector.recieveMessage('die', this);
     }

     getMessage(message) {
         console.log(`${this.name} recieved message: ${message}`);
     }
 }

 export class PlayerMediator{
     constructor() {
         this.players = {};
     }

     recieveMessage(type, player) {
         this[type](player);
     }

     add(player) {
         this.players[player.teamColor] = this.players[player.teamColor] || [];
         this.players[player.teamColor].push(player);
         this.getAllPlayerExceptThis(player).forEach((p) => {
             p.getMessage(`player ${player.name} added.`);
         });
     }

     remove(player) {
         let index = this.players[player.teamColor].indexOf(player);
         this.players[player.teamColor][index].status = 'disconnect';
         this.getAllPlayerExceptThis(player).forEach((p) => {
             p.getMessage(`player ${player.name} disconnected.`);
         });
         if (this.verifyOver(player.teamColor)) {
             this.gameOver(player.teamColor)
         }
     }

     die(player) {
         let index = this.players[player.teamColor].indexOf(player);
         this.players[player.teamColor][index].status = 'die';
         this.getAllPlayerExceptThis(player).forEach((p) => {
             p.getMessage(`player ${player.name} dead.`);
         });
         if (this.verifyOver(player.teamColor)) {
             this.gameOver(player.teamColor)
         }
     }

     getAllPlayerExceptThis(player) {
         let ret = [];
         for (let t of Object.keys(this.players)) {
             for (let p of this.players[t]) {
                 if (player !== p) {
                     ret.push(p);
                 }
             }
         }
         return ret;
     }

     verifyOver(teamColor) {
         for (let player of this.players[teamColor]) {
             if (player.status === 'live') {
                 return false;
             }
         }
         return true
     }

     gameOver(teamColor) {
         for (let t of Object.keys(this.players)) {
             for (let player of this.players[t]) {
                 if (teamColor === player.teamColor) {
                     player.lose();
                 } else {
                     player.win();
                 }
             }
         }
     }
 }