Quicklink: Prefetching Visible Links to Accelerate Page Load

Quicklink is a tiny JavaScript library that prefetches URLs visible in the viewport during idle time, accelerating subsequent page loads.

It works by detecting links with the Intersection Observer API, waiting for browser idle via requestIdleCallback , checking connection speed through navigator.connection.effectiveType or data‑saving mode, and prefetching URLs using <link rel="prefetch"> or XHR, optionally switching to fetch() for higher priority.

The project aims to provide a solution under 1 KB gzipped; it can be installed with npm install --save quicklink or loaded from https://unpkg.com/quicklink .

After initialization, quicklink automatically prefetches links in the viewport. Usage examples include calling quicklink() after the load event, importing it as an ES module, or invoking it with a specific DOM element or a custom URL array.

The API accepts an options object with parameters such as el (target element), urls (static URL list), timeout (idle callback timeout), timeoutFn (custom timeout handler), and priority (boolean to use fetch() instead of rel=prefetch ).

Browser support is progressive: modern browsers support it natively; with the Intersection Observer polyfill it also works in Safari and IE9+. A polyfill for requestIdleCallback may be required for older browsers.

Demos demonstrate up to a 4‑second performance gain, and related projects include Gatsby’s prefetching and Guess.js, which adds data‑driven prefetching.

The library is released under the Apache‑2.0 license.