The concept of an “incremental build” is that, when using some kind of generator that builds all the files that make for a website, rather than rebuilding 100% of those files every single time, it only changes the files that need to be changed since the last build. Seems like an obviously good idea, but in practice I’m sure it’s extremely tricky. How do you know what exactly which files will change and which won’t before building?
I don’t have the answer to that, but Gatsby has it figured out. Faster local builds is half the joy, the other half is that deployment also becomes faster, as the files that need to move around are far fewer.
I’d say incremental builds are a pretty damn big deal. I like seeing these hurdles get cleared Jamstack-land. I’m linking to the Netlify blog post here as getting it going on Netlify requires you to enable their “build plugins” feature which is also a real ahead-of-the-game feature, allowing you to run code during different parts of CI/CD with a really clean syntax.