Svelte is a somewhat different JavaScript framework. How come? Because it replaces the traditional approach used by React or Vue where the browser takes care of most of the work with a novel focus on a compile step. Thus, Svelte generates code that updates the DOM whenever the state changes. This reduces the size of the transferred files and provides your app with a better loading and run-time performance. 

Svelte is a free and open-source front end compiler created by Rich Harris and maintained by the Svelte core team members. Svelte applications do not include framework references.