configAxios.js

import axios from 'axios';

const URLs = {
  merchant: process.env.MERCHANT_API,
  order: process.env.ORDER_API,
  customer: process.env.CUSTOMER_API
};

/**
 * Create a new Axios instance
 * @see https://github.com/mzabriskie/axios#creating-an-instance
 */
const instanceCreator = (domain, subdomain = '') => {
  if (!domain || !URLs[domain]) {
    throw new Error('domain is needed to instance an api');
  }

  const baseURLArray = [URLs[domain]];

  if (subdomain) {
    baseURLArray.push(subdomain);
  }

  const options = {
    baseURL: baseURLArray.join('/')
  };

  // Create the interceptors callbacks
  const requestInterceptorSuccess = async request => {
    // adicionar os headers de autorização e x-merchantId
    const token = await getIdToken();

    if (token) {
      request.headers['Authorization'] = await getIdToken();
    }

    if (request.merchantId) {
      request.headers['X-MerchantId'] = request.merchantId;
    }

    return Promise.resolve(request);
  };

  /************* TRABALHAMOS ATÉ AQUI *************/

  const requestInterceptorError = error => {
    // tratamento de erro genérico
    return Promise.reject(error);
  };

  const responseInterceptorSuccess = response => {
    return Promise.resolve(response);
  };

  const responseInterceptorError = error => {
    // tratamento de erro genérico
    error.errorMessage = errorMessage[error.statusText];

    return Promise.reject(error);
  };

  // Create instance and set up interceptors
  const instance = axios.create(options);
  instance.interceptors.request.use(
    requestInterceptorSuccess,
    requestInterceptorError
  );
  instance.interceptors.response.use(
    responseInterceptorSuccess,
    responseInterceptorError
  );

  return instance;
};

export default instanceCreator;


// EXEMPLOS DE USO
// coupons-api.js
const CouponsAPI = instanceCreator('merchant', '/coupons')

.
.
.

const response = CouponsAPI.post(`/`, {
    name: 'HALLOWIN',
    value: 10,
    category: 'PRODUCTS_AMOUNT'
}, {
    merchantId: 'xpto'
})

response.data // json
response.status // number