fetch-cached/build/index.js

Fetch with response cache

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = fetchCached;
/*
* Returns a fetch function wrapped with cache to be used as normal fetch
*/

function fetchCached(options) {
  if (!options || !options.fetch) throw Error('fetch is a required option');
  if (!options || !options.cache) throw Error('cache is a required option');

  var fetch = options.fetch;
  var cache = options.cache;


  function setCache(key, data) {
    data.then(function (value) {
      cache.set(key, value);
    });
  }

  function getCache(key) {
    var value = cache.get(key).then(function (data) {
      if (!data) return null;

      return Promise.resolve({
        ok: true,
        url: key,
        status: 200,
        statusText: 'OK',
        json: function json() {
          return Promise.resolve(JSON.parse(data));
        },
        text: function text() {
          return Promise.resolve(data);
        }
      });
    });

    return value;
  }

  return function cachedFetch(url) {
    var options = arguments.length <= 1 || arguments[1] === undefined ? {} : arguments[1];

    // return plain fetch for non-GET requests
    if (options.method && options.method !== 'GET') {
      return fetch(url, options);
    }

    var response = getCache(url).then(function (cached) {
      // return the cached result if it exist
      if (cached) return cached;

      // return fetch for non-cached requests and set cache
      return fetch(url, options).then(function (response) {
        setCache(url, response.clone().text());

        return Promise.resolve(response);
      });
    });

    return response;
  };
}