cab.js

const fetchJson = (url, opts = {}) => fetch(url, {
  method: opts.method,
  headers: {'Content-Type': 'application/json'},
  body: opts.body && JSON.stringify(opts.body),
}).then(res => res.json());

export default {
  create: body => fetchJson(API_URL, {
    method: 'POST',
    body,
  }),

  read: id => fetchJson(`${API_URL}/${id}`),

  update: (id, body) => fetchJson(`${API_URL}/${id}`, {
    method: 'PUT',
    body,
  }),

  delete: id => fetchJson(`${API_URL}/${id}`, {
    method: 'DELETE',
  }),
};