Let's face, it…No one likes a slow app. And with Progressive Web Apps, a great experience requires everything to be fast. This is not a vague statement either, research shows that about half of your users will leave your app if it does not load within 3 seconds over the network. Thankfully, there's APIs in place to help you achieve faster loading, with little effort. We'll look at rel=preload and how this little property, can speed up our loading performance.
rel=preload is a relatively new value you can use for the rel attribute of the link element. It is a special value that the browser can read, and know that the resource it's attached to is important. Once a browser sees a link element with preload, it will automatically start downloading the asset instantly.
But how is this different from the browsers normal flow? Well, when a browser request an html page, the parse will read the document, and pull