> Http pipelining should make it fast to load them from your server with the rest
That's true, but it should be emphasized that it's only fast if you bundle your dependencies, too.
Browsers and web developers haven't been able to find a way to eliminate a ~1ms/request penalty for each JS file, even if the files are coming out of the local cache.
If you're making five requests, that's fine, but if you're making even 100 requests for 10 dependencies and their dependencies, there's a 100ms incentive to do at least a bundle that concatenates your JS.
And once you've added a bundle step, you're a few minutes away from adding a bundler that minifies, which often saves 30% or more, which is usually way more than you probably saved from just concatenating.
> The only advantage to using one of those cdn-hosted versions is that it might help with browser caching
And that is not true. Browsers have separate caches for separate sites for privacy reasons. (Before that, sites could track you from site to site by seeing how long it took to load certain files from your cache, even if you'd disabled cookies and other tracking.)
That's true, but it should be emphasized that it's only fast if you bundle your dependencies, too.
Browsers and web developers haven't been able to find a way to eliminate a ~1ms/request penalty for each JS file, even if the files are coming out of the local cache.
If you're making five requests, that's fine, but if you're making even 100 requests for 10 dependencies and their dependencies, there's a 100ms incentive to do at least a bundle that concatenates your JS.
And once you've added a bundle step, you're a few minutes away from adding a bundler that minifies, which often saves 30% or more, which is usually way more than you probably saved from just concatenating.
> The only advantage to using one of those cdn-hosted versions is that it might help with browser caching
And that is not true. Browsers have separate caches for separate sites for privacy reasons. (Before that, sites could track you from site to site by seeing how long it took to load certain files from your cache, even if you'd disabled cookies and other tracking.)