Strategy Patterns

strategy.ts

interface Strategy {
  authenticate(args: any[]): boolean;
}

class Authenticator {
  strategies: Record<string, Strategy> = {};

  use(name: string, strategy: Strategy) {
    this.strategies[name] = strategy;
  }

  authenticate(name: string, ...args: any) {
    if (!this.strategies[name]) {
      console.error("Authentication policy has not been set!");
      return false;
    }
    return this.strategies[name].authenticate.apply(null, args);
  }
}

class WechatStrategy implements Strategy {
  authenticate(args: any[]) {
    const [token] = args;
    if (token !== "wc123456") {
      console.error("Wechat account authentication failed!");
      return false;
    }
    console.log("Wechat account authentication succeeded!");
    return true;
  }
}

class LocalStrategy implements Strategy {
  authenticate(args: any[]) {
    const [username, password] = args;
    if (username !== "semlinker" || password !== "888") {
      console.log("Incorrect username or password!");
      return false;
    }
    console.log("Account and password authentication succeeded!");
    return true;
  }
}

const auth = new Authenticator();

auth.use("wechat", new WechatStrategy());
auth.use("local", new LocalStrategy());

function login(mode: string, ...args: any) {
  return auth.authenticate(mode, args);
}

login("wechat", "wc123");
login("local", "semlinker", "666");