How To Write Services Using JavaScript

final-interceptor.js

console.log("Welcome to How To Write Services Using JavaScript")

const http = {
  cb: [],
  intercept(cb) {
    this.cb.push(cb);
  },
  async get(url, options = {}) {
    return this.request(url, null, options)
  },
  async post(url, body = {}, options = {}) {
    return this.request(url, body, { ...options, method: "POST" })
  },
  async put(url, body = {}, options = {}) {
    // TODO
  },
  async delete(url, body = {}, options = {}) {
    // TODO
  },
  async request(url, body = {}, options = {}) {
    options.headers = {
      'Content-Type': "application/json",
      ...options.headers,
    };
    // Iterate all interceptors to modify the options
    if (this.cb.length) {
      for (let fn of this.cb) {
        options = fn(options, url);
      }
    }
    const res = await fetch(url, {
      body: body ? JSON.stringify(body) : undefined,
      ...options,
    });
    return res.json()
  }
}
const authInterceptor = (options, url) => {
  if (/users/.test(url) && options.method === "POST")
    options.headers.Authorization = 'Bearer sometoken';
  return options
}
http.intercept(authInterceptor)

const apiHost = `http://localhost:3000`
const services = {
  getUsers() {
    return http.get(`${apiHost}/users`)
  },
  createUser(user) {
    return http.post(`${apiHost}/users`, user)
  },
  updateUser({ id, ...user }) {
    return http.put(`${apiHost}/users/${id}`, user)
  }
}

const id = Date.now();
services.getUsers().then(console.log)
services.createUser({
  "id": id,
  "name": "deepak2",
  "age": 32,
  "address": "not found2"
}).then(console.log)