We’re a bit light on features this month because we’re working on a new site quality report. More on that next month. In the meantime, we have some helpful additions:

React v16 is innovative. It comes with better error handling and new features like Error Boundaries, Fragment, Portals, Lazy, Memo, a new Context API, Hooks, Suspense, and concurrent rendering. I have been upgrading a large React code base from React v15 to React v16. This upgrade was clearly necessary but implementing is nontrivial on a large codebase. Thanks to the React team at Facebook, the migration path looks easy. Unfortunately, this was not the case.

Nothing changed in your code. All of a sudden, a tidal wave of errors start happening for Microsoft Edge users. What the heck happened?

On August 28th, 2019, many TrackJS customers saw a sudden surge in errors from Microsoft Edge browsers: Failed to construct 'Request': Invalid Argument and Failed to execute 'fetch()' on 'Window': Invalid argument".

Web sites continue to bloat with oversized images, custom fonts, and too much JavaScript. The huge amount of poor performing JavaScript on many sites drags desktop browsers and crushes low-end mobile devices. No one wants to work on sites like that.

To make your site better, faster, and lighter, we’ve compiled some high-level best practices to reduce your JavaScript load.

Wrapping JavaScript functions lets you add common logic to functions you do not control, like native and external functions. Many JavaScript libraries, like the TrackJS agents, need to wrap external functions to do their work. Adding wrappers allows us to listen for Telemetry, errors, and logs in your code, without you needing to call our API explicitly.

Todd and David discuss tools and techniques to debug remote devices, such as phones and kiosk computers.