Strategy.ts

class User {
    githubToken: string;
    jwtToken: string;
}

interface AuthStrategy {
    auth(user: User): boolean;
}

class Auth {
    constructor(private strategy: AuthStrategy) {}

    setStrategy(strategy: AuthStrategy) {
        this.strategy = strategy
    }

    public authUser(user: User): boolean {
        return this.strategy.auth(user);
    }
}

class JWTStrategy implements AuthStrategy {
    auth(user: User): boolean {
        if (user.jwtToken) {
            return true
        }
        return false
    }
}

class GitHubStrategy implements AuthStrategy {
    auth(user: User): boolean {
        if (user.githubToken) {
            return true
        }
        return false
    }
}

const user = new User();
user.jwtToken = 'token';
const auth = new Auth(new JWTStrategy())
auth.authUser(user);
console.log(auth)
auth.setStrategy(new GitHubStrategy())
console.log(auth)