BuyingFlow.ts

class BuyingFlow extends BasePage {
  ...
}

class BuyingFlow implements BasePageI {
  load() {}
  waitForInitloaded() {}
}

const BuyingFlow: BasePageI = {
  load() {},
  waitForInitloaded() {},
};

const BuyingFlow = {
  load() {},
  waitForInitloaded() {},
};