IntroduceInstanceDelegator.ts

// a utility class :(
export class BankingServices {
    public static updateAccountBalance(userId: number, amount: Money): void {
        // some code to update the account balance
    }
    
    // more methods...
}

export class User {
    private id: number;
    
    constructor(id: number) {
        this.id = id;
    }

    // more code...

    public updateBalance(amount: Money): void {
        // using the utility class :(
        BankingServices.updateAccountBalance(this.id, amount);
    }
    
    // more code...
}

//////////////////////////////////////////////

// Introduce instance delegator in the utility class

export class BankingServices {
    public static updateAccountBalance(userId: number, amount: Money): void {
        // some code to update the account balance
    }
    
    //!! the instance delegator <- now we can Subclass & Override Method here!
    public updateBalance(userId: number, amount: Money): void {
        // it calls the static method
        BankingServices.updateAccountBalance(userId, amount);
    }
    
    // more methods...
}