fetchWrapper.js

const localStorageKey = '__bookshelf_token__'
function client(endpoint, {body, ...customConfig} = {}) {
  const token = window.localStorage.getItem(localStorageKey)
  const headers = {'content-type': 'application/json'}
  if (token) {
    headers.Authorization = `Bearer ${token}`
  }
  const config = {
    method: body ? 'POST' : 'GET',
    ...customConfig,
    headers: {
      ...headers,
      ...customConfig.headers,
    },
  }
  if (body) {
    config.body = JSON.stringify(body)
  }
  return window
    .fetch(`${process.env.REACT_APP_API_URL}/${endpoint}`, config)
    .then(async response => {
      if (response.status === 401) {
        logout()
        window.location.assign(window.location)
        return
      }
      const data = await response.json()
      if (response.ok) {
        return data
      } else {
        return Promise.reject(data)
      }
    })
}

function logout() {
  window.localStorage.removeItem(localStorageKey)
}

https://kentcdodds.com/blog/replace-axios-with-a-simple-custom-fetch-wrapper?ck_subscriber_id=653418166

import {client} from './api-client'

function create(listItemData) {
  return client('list-items', {body: listItemData})
}

function read() {
  return client('list-items')
}

function update(listItemId, updates) {
  return client(`list-items/${listItemId}`, {
    method: 'PUT',
    body: updates,
  })
}

function remove(listItemId) {
  return client(`list-items/${listItemId}`, {method: 'DELETE'})
}

export {create, read, remove, update}