example of service

service.ts

import Analytics = require('analytics-node');
import { inject, injectable, named } from 'inversify';
import { getRepository } from 'typeorm';
import { ApplicationCharge } from '../entities/ApplicationCharge';
import { ChargeMapper } from '../entities/mappers/ChargeMapper';
import { Merchant } from '../entities/Merchant';
import { MerchantGateway } from '../gateway/MerchantGateway';

export interface Query {
  shop: string;
  path_prefix: string;
  timestamp: number;
  signature: string;
}

@injectable()
export class MerchantService {

  constructor(@inject('MerchantGateway') @named('Shopify') protected merchantGateway: MerchantGateway,
              @inject('Logger') protected logger: any,
              @inject('Analytics') @named('Segment') protected analytics: Analytics,
              @inject('Cache') protected cache: any) {
  }

  public async getOne(query: Query, trackAnalytics: boolean = true, fetchRemoteCharges: boolean = false): Promise<Merchant> {
    const repository = getRepository(Merchant);
    const merchant = await repository.findOne({ domain: query.shop}, {relations: ['status', 'applicationCharge', 'auth']});
    if (fetchRemoteCharges) {
      try {
        const remoteApplicationCharges = await this.merchantGateway.listRecurringCharges(merchant.auth[0].token, merchant.domain);
        if (remoteApplicationCharges.recurring_application_charges
          && remoteApplicationCharges.recurring_application_charges.length > 0) {
          // if we have an active charge, set that one to update locally
          let chargeToSave = remoteApplicationCharges.recurring_application_charges.find((charge: any) => charge.status === 'active');
          // if we have neither, set the first one as the one to update
          if (!chargeToSave) {
            chargeToSave = remoteApplicationCharges.recurring_application_charges[0];
          }
          merchant.applicationCharge = await MerchantService.updateApplicationCharge(chargeToSave, merchant);
          if (trackAnalytics) {
            this.analytics.identify({
              traits: {
                email: merchant.email,
                merchant: merchant.domain,
                requirementApplicationChargesAccepted: merchant.applicationCharge.status,
              },
              userId: merchant.id.toString(),
            });
          }
        }
      } catch (e) {
          this.logger.error(`failed to fetch recurring charge for merchant with error ${e}`,
            { meta: {service: 'MerchantService', merchant: query.shop, stackTrace: e.stack, error: e}});
      }
    }
    return merchant;
  }

  public async completeOnboarding(query: Query): Promise<Merchant> {
    const repository = getRepository(Merchant);
    const merchant = await repository.findOne({ domain: query.shop});
    merchant.isOnboarded = true;
    this.analytics.identify({userId: merchant.id.toString()},
      (err, data) => {
      if (err) {
        this.logger.error(`error sending identify call for merchant ${merchant.email}`,
          {message: err.message, name: err.name});
        return;
      }
      this.analytics.track({
        event: 'Merchant Onboarded',
        properties: {},
        userId: merchant.id.toString(),
      });
    });
    return repository.save(merchant);
  }

  public async disableDummyMode(query: Query): Promise<Merchant> {
    const repository = getRepository(Merchant);
    const merchant = await repository.findOne({ domain: query.shop});
    merchant.isDummyDataModeEnabled = false;
    return repository.save(merchant);
  }

  private static async updateApplicationCharge(remoteApplicationCharge: any, merchant: Merchant): Promise<ApplicationCharge> {
    const repository = getRepository(ApplicationCharge);
    if (merchant.applicationCharge) {
      await repository.delete(merchant.applicationCharge.id);
    }
    let localApplicationCharge = await repository.findOne(remoteApplicationCharge.id);
    if (!localApplicationCharge) {
      localApplicationCharge = ChargeMapper.fromShopifyApplicationCharge(remoteApplicationCharge);
      localApplicationCharge.merchant = merchant;
      return repository.save(localApplicationCharge);
    }
    localApplicationCharge = ChargeMapper.fromShopifyApplicationCharge(remoteApplicationCharge);
    return repository.save(localApplicationCharge);
  }
}