"Just JavaScript" can mean different things to different developers. For the author, it implies that code should function without custom transformations. They want clarity about what their code does and expect normal refactoring to work seamlessly. While the author makes an exception for TypeScript and JSX, which require transforms but are widely accepted and supported by modern runtimes like Deno and Bun, they still acknowledge that browsers need a way to bundle these for use. When evaluating frameworks, the author analyzes React Router, Svelte, React, and Remix 3 against their definition. React Router is mostly "just JavaScript," but its integration with Vite introduces some runtime changes, particularly with route modules that alter how code executes based on its placement. Svelte, on the other hand, isn’t "just JavaScript" because it operates as its own language, embedding JavaScript within a framework that uses distinct semantics. React used to fit the "just JavaScript" mold but now incorporates directives that require custom transforms, complicating its use. Finally, Remix 3 aligns with the "just JavaScript" philosophy, emphasizing runtime design that avoids relying on static analysis or bundling, ensuring that all packages function independently of build tools.