Axios requests interceptor example

axiosService.js

import Credentials from "./Credentials";
const axios = require("axios");

const http = axios.create(); // Creates new axios instance

const credentials = new Credentials(); // Gets access to all credentials functions
http.interceptors.request.use(
  async config => {
    const token = await credentials.getCredentials();  // Gets credentials from localStorage
    if (token) config.headers.Authorization = `Bearer ${token}`; // Inserts credentials as bearer token in request headers
    return config;
  },
  error => {
    return Promise.reject(error);
  }
);

// Exposes all API end points as appropriate functions
export default {
  api: {
    getChapters() {
      return http.get(`${process.env.REACT_APP_API_BASE_URL}/api/v1/chapters`);
    },
    getSpecificChapter(chapter) {
      return http.get(`${process.env.REACT_APP_API_BASE_URL}/api/v1/chapters/${chapter}`);
    },
    getVerses() {
      return http.get(`${process.env.REACT_APP_API_BASE_URL}/api/v1/verses`);
    },
    getVersesFromChapter(chapter) {
      return http.get(
        `${process.env.REACT_APP_API_BASE_URL}/api/v1/chapters/${chapter}/verses`
      );
    },
    getSpecificVerse(chapter, verse) {
      return http.get(
        `${process.env.REACT_APP_API_BASE_URL}/api/v1/chapters/${chapter}/verses/${verse}`
      );
    },
  },
};