next.js/examples/with-data-prefetch/README.md

Example app with prefetching data

How to use

Using create-next-app

Download create-next-app to bootstrap the example:

npm i -g create-next-app
create-next-app --example with-data-prefetch with-data-prefetch-app

Download manually

Download the example or clone the repo:

curl https://codeload.github.com/zeit/next.js/tar.gz/canary | tar -xz --strip=2 next.js-canary/examples/with-data-prefetch
cd with-data-prefetch

Install it and run:

npm install
npm run dev

Deploy it to the cloud with now (download)

now

The idea behind the example

Next.js lets you prefetch the JS code of another page just adding the prefetch prop to next/link. This can help you avoid the download time a new page you know beforehand the user is most probably going to visit.

In the example we'll extend the Link component to also run the getInitialProps (if it's defined) of the new page and save the resulting props on cache. When the user visits the page it will load the props from cache and avoid any request.

It uses sessionStorage as cache but it could be replaced with any other more specialized system. Like IndexedDB or just an in-memory API with a better cache strategy to prune old cache and force new fetching.

This example is based on the ScaleAPI article explaining this same technique.

Note: it only works in production environment. In development Next.js just avoid doing the prefetch.