api_helper.js

import { getAccessToken } from './session';

// quick and dirty serializer

function serializeObjectToQueryString(obj) {
  if (!obj) { return ""; }
  const str = [];
  for (var prop in obj) {
    if (obj.hasOwnProperty(prop)) {
      str.push(encodeURIComponent(prop) + "=" + encodeURIComponent(obj[prop]));
    }
  }
  return '?' + str.join("&");
}

const successHandler = (success, failure) => response => {
  if (response.status >= 200 && response.status < 300) {
    return response.json().then(json => {
      if (success) {
        success(json)
      }
    })
  } else {
    return response.json().then(json => {
      const error = new Error(response.statusText)
      error.type = response.status
      error.json = json
      if (failure) {
        failure(error);
      } else {
        throw error;
      }
    })
  }
}

const errorHandler = failure => response => {
  failure(response)
}

// data is any data to be sent in body or query string
// success is callback for success status codes
// failure is callback for error status codes
// error is callback for network errors

const defaultOptions = {
  data: null,
  success: null,
  failure: null,
  error: null
}

function get(url, options=defaultOptions) {
  return fetch(url + serializeObjectToQueryString(options.data), {
    method: 'get',
    headers: {
      'Authorization': getAccessToken()
    }
  })
  .then(successHandler(options.success, options.failure))
  .catch(errorHandler(options.error || options.failure))
}

function post(url, options=defaultOptions) {
  return fetch(url, {
    method: 'post',
    headers: {
      'Authorization': getAccessToken(),
      'Accept': 'application/json',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify(options.data)
  })
  .then(successHandler(options.success, options.failure))
  .catch(errorHandler(options.error || options.failure))
}

export default { get, post }