Like Electron, with Tauri you write your GUIs with HTML, CSS, and Javascript. Electron uses Node for the client-side non-GUI functionality, while Tauri instead uses Rust binaries to accomplish same. That's the alternative part. Node is not needed at all in the final build, although it may be used to create your app before bundling for release.
Maybe we need to be more clear about how nodejs CAN be used in the construction of a Tauri app, and that it is neither a requirement to make a Tauri app nor a component that is shipped with a Tauri app.