Preview.js is an attempt at helping web developers achieve and maintain flow state as much as possible when creating and tweaking UI components. I believe this is best done by reducing unnecessary context switching and optimising for fast feedback.
When you use Preview.js, you don't need to spin up an app server and click through a specific flow to look at your component. You don't need to write component "stories" and spin up Storybook. You just click "Preview" in your IDE and see it right there, next to your code, updated instantly as you type.
Preview.js doesn't aim to replace your app server or Storybook. They each have their role to play! Its purpose is solely to help you achieve that sweet, sweet state of flow while you're developing.
I'm the founder of Zenc Labs, a developer happiness engineering company in Sydney. Zenc Labs is bootstrapped, so it's a small team of one :)
Feel free to reach out if you need help integrating Preview.js with your codebase!