cacheability

A utility class to parse, store and print http cache headers.

Installation

yarn add cacheability

Documentation

Initialization

The constructor takes either a Headers instance, object literal of header key/values, cache-control header field value or Cacheability metadata object, parses it, if required, and then stores the result on the Cacheability instance's metadata property.

import { Cacheability } from "cacheability";

const headers = new Headers({
  "cache-control": "public, max-age=60",
  "content-type": "application/json",
  "etag": "33a64df551425fcc55e4d42a148795d9f25f89d4",
});

const cacheability = new Cacheability({ headers });

const { cacheControl, etag, ttl } = cacheability.metadata;
// cacheControl is { maxAge: 60, public: true }
// etag is 33a64df551425fcc55e4d42a148795d9f25f89d4
// ttl is 1516060712991 if Date.now is 1516060501948

Properties

metadata

The property holds the Cacheability instance's parsed cache headers data, including cache control directives, etag, and a derived TTL timestamp.

Methods

checkTTL

The method checks whether the TTL timestamp stored in the Cacheability instance is still valid, by comparing it to the current timestamp.

const cacheability = new Cacheability({ cacheControl: "public, max-age=3" });

// One second elapses...

const isValid = cacheability.checkTTL();
// isValid is true

// Three seconds elapse...

const isStillValid = cacheability.checkTTL();
// isStillValid is false

printCacheControl

The method prints a cache-control header field value based on the Cacheability instance's metadata. The max-age and/or s-maxage are derived from the TTL stored in the metadata.

const cacheability = new Cacheability({ cacheControl: "public, max-age=60, s-maxage=60" });

// Five seconds elapse...

const cacheControl = cacheability.printCacheControl();
// cacheControl is "public, max-age=55, s-maxage=55"

Additional documentation can be found on the Cacheability github pages.

Changelog

Check out the features, fixes and more that go into each major, minor and patch version.

License

Cacheability is MIT Licensed.