How to use the testdouble/dist/testdouble.function function in testdouble

beforeEach(() => {
    renderOptions = {
      createOrder: () => ZalgoPromise.resolve('order-id'),
      onApprove:   td.function(),
      onError:     td.function(),
      fields:      {
        number: {
          selector: '#credit-card'
        }
      }
    };

    fakeTokenizationPayload = {
      payment_source: {
        card: {
          last_digits: '1111',
          card_type:   'VISA'
        }
      },
      links: []

beforeEach(() => {
    renderOptions = {
      createOrder: () => ZalgoPromise.resolve('order-id'),
      onApprove:   td.function(),
      onError:     td.function(),
      fields:      {
        number: {
          selector: '#credit-card'
        }
      }
    };

    fakeTokenizationPayload = {
      payment_source: {
        card: {
          last_digits: '1111',
          card_type:   'VISA'
        }
      },
      links: []
    };

beforeEach(() => {
      button = document.createElement('button');
      button.id = 'button';
      renderOptions.createOrder = td.function();


      if (document.body) {
        document.body.appendChild(button);
      }

      td.when(renderOptions.createOrder()).thenReturn(orderId);
    });