fetch-json-cache

fetch-json-cache

Caches fetched JSON and updates it when the endpoint's ETag changes. If a cached record exists, it reuses that record only when the ETag request fails with ENOTFOUND or the legacy SSL23_GET_SERVER_HELLO error. Other errors propagate, and { force: true } bypasses this fallback.

npm install fetch-json-cache

var Cache = require('fetch-json-cache');
var cache = new Cache('/path/to/cache');
var endpoint = 'https://registry.npmjs.org/fetch-json-cache';

async function run() {
  var json = await cache.get(endpoint);
  console.log(json.name);
  await cache.clear();
}

run().catch(console.error);

Pass { force: true } as the second argument to fetch and replace the cached value regardless of its ETag. Use cache.getSync(endpoint) to read an existing cached value without making a request.

Callback forms are also available:

cache.get(endpoint, function (err, json) {
  if (err) return console.error(err);
  console.log(json.name);
});

Pass a transform function in the constructor options to change the parsed JSON before it is stored.