gistfile1.txt

class Wallet {

  constructor (patient, currency) {
    this.patient = patient;
    this.currency = currency;
  }
  
  async getBalanceAsync () {
    // sum `amount` aggregation with patient and currency filter
    return 0;
  }
  
  async addTransaction ({ type: any, amount: number, description: string: metadata?: any }) {
    const currentBalance = await getBalanceAsync();
    
    if ((currentBalance + amount) < 0) {
      return Promise.reject(new Error("insufficient balance"));
    }
  
    let transaction = new WalletTransaction ({
      patient: this.patient,
      currency: this.currency,
      // balance: currentBalance + amount,
      amount,
      description,
      type,
      metatada,
    });
    
    return transaction.save();
  }
  
  async execDeposit ({ amount: number, description: string, metadata?: any }) {
    return this.addTransaction({ 
      type: "deposit",
      description: description,
      metadata,
      amount
    });
  }
  
 async execRefund ({ amount: number, description: string, metadata?: any }) {
    return this.addTransaction({ 
      type: "refund",
      description: description,
      metadata,
      amount: amount
    });
  }
  
  async execPayment ({ amount: number, description: string, metadata?: any }) {
    return this.addTransaction({ 
      type: "payment",
      description: description,
      metadata,
      amount: amount * -1
    });
  }
  
 async addCashback ({ amount: number, description: string, metadata?: any }) {
    return this.addTransaction({ 
      type: "cashback",
      description: description,
      metadata,
      amount: amount
    });
  }
}