re: I'm Addy Osmani, Ask Me Anything! VIEW POST

re: Do you think the recent rise in popularity of single page applications using React/Angular/Vue have been good for web performance? To me, it seems ...

Great question :) A lot of the sites I profile these days don't perform well on average mobile phones, where a slower CPU can take multiple seconds to parse and compile large JS bundles. To the extent that we care about giving users the best experience possible, I wish our community had better guardrails for keeping developers off the "slow" path.

React/Preact/Vue/Angular (with the work they're doing on Ivy) are not all that costly to fetch over a network on their own. The challenge is that it's far too easy these days to "npm install" a number of additional utility libraries, UI components, routers..everything you need to build a modern app, without keeping performance in check. Each of these pieces has a cost to it and it all adds up to larger bundles. I wish our tools could yell at you when you're probably shipping too much script.

I'm hopeful we can embrace performance budgets more strongly in the near future so that teams are able to learn to live within the constraints that can guarantee their users can load and use your sites in a reasonable amount of time.

SPAs vs SSR sites: Often we're shipping down a ton of JavaScript to just render a list of images. If this can be done more efficiently on the server-side by just sending some HTML to your users, go for it! If however the site needs to have a level of interaction powered by JavaScript, I heavily encourage using diligent code-splitting and looking to patterns like PRPL for ensuring you're not sending down so much code the main thread is going to stay blocked for seconds.


Thanks for responding! PRPL is a new pattern to me, hopefully with more awareness we will be able to use it and techniques like it to get better performance.

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