Typescript 职责链模式（Chain of Responsibility）

普通折扣: 消费不满100元，不打折
黄金折扣: 消费满100元，打9折
铂金折扣: 消费满500元，打8折
钻石折扣: 消费满1000元，打7折

/* handler-abstract-class.ts */
export abstract class HandlerAbstractClass {
    protected name: string;

    protected higherLevel: HandlerAbstractClass;

    constructor (name: string) {
        this.name = name;
    }

    public setHigherLevel (higherLever: HandlerAbstractClass) {
        this.higherLevel = higherLever;
    }

    public abstract handlerMessage (money: number)
}

/* level-1.ts */
import { HandlerAbstractClass } from ‘./handler-abstract-class‘;

export class Level1 extends HandlerAbstractClass {
    public handlerMessage(money: number) {
        if (money < 100) {
            console.log(`您消费${money}元，当前折扣为${this.name}折扣，还需支付${money}元`);
        } else {
            this.higherLevel.handlerMessage(money);
        }
    }
}
/* level-2.ts */
import { HandlerAbstractClass } from ‘./handler-abstract-class‘;

export class Level2 extends HandlerAbstractClass {
    public handlerMessage(money: number) {
        if (money < 500) {
            console.log(`您消费${money}元，当前折扣为${this.name}折扣，还需支付${money * 0.8}元`);
        } else {
            this.higherLevel.handlerMessage(money);
        }
    }
}
/* level-3.ts */
import { HandlerAbstractClass } from ‘./handler-abstract-class‘;

export class Level3 extends HandlerAbstractClass {
    public handlerMessage (money: number) {
        if (money < 1000) {
            console.log(`您消费${money}元，当前折扣为${this.name}折扣，还需支付${money * 0.7}元`);
        } else {
            this.higherLevel.handlerMessage(money);
        }
    }
}
/* level-4.ts */
import { HandlerAbstractClass } from ‘./handler-abstract-class‘;

export class Level4 extends HandlerAbstractClass {
    public handlerMessage(money: number) {
        console.log(`您消费${money}元，当前折扣为${this.name}折扣，还需支付${money * 0.6}元`);
    }
}

/* client.ts */
import { Level1 } from ‘./level-1‘;
import { Level2 } from ‘./level-2‘;
import { Level3 } from ‘./level-3‘;
import { Level4 } from ‘./level-4‘;

export class Client {
    public static getDiscount(money: number) {
        const level4 = new Level4(‘钻石‘);
        const level3 = new Level3(‘铂金‘);
        const level2 = new Level2(‘黄金‘);
        const level1 = new Level1(‘普通‘);
        level2.setHigherLevel(level3);
        level1.setHigherLevel(level2);
        level1.handlerMessage(money);
    }
}
Client.getDiscount(1176);